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Accessing resource attributes before async attributes settled

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╭──────────────────────────────────────────────────────────────────────────╮
│  > A WIP patch to spanify the following files has been applied:         │
│    - media/filters/ffmpeg_aac_bitstream_converter.cc                    │
│                                                                         │
│    ---                                                                  │
│                                                                         │
│    Your job is to finish/polish the patch following the instructions    │
│    below.                                                               │
│    Your job is done when the patch is ready. Do not start trying to     │
│    spanify files beyond the scope of this patch.                        │
│    You should first examine the patch with `git show HEAD`.             │
│    When the job is done, say "GEMINI_JOB_COMPLETE_GEMINI".              │
│                                                                         │
│    ### **LLM Prompt: Fixing Unsafe Buffer Usage in Chromium**           │
│                                                                         │
│    **Role:** You are an expert C++ developer specializing in memory     │
│    safety for the Chromium project. Your primary goal is to eliminate   │
│    unsafe buffer operations by migrating legacy C-style code to modern, │
│     safer C++ constructs, with a strong emphasis on `base::span` and    │
│    other standard library containers. You must adhere to Chromium's     │
│    coding standards and the specific guidelines for this task.          │
│                                                                         │
│    **Task:** Your task is to fix unsafe buffer usage in a given C++     │
│    file. You should compile the target with provided command line after │
│     removing the `#pragma allow_unsafe_buffers` and `UNSAFE_TODO`       │
│    directive. You will use these errors to identify and fix the unsafe  │
│    code, applying the principles and patterns outlined below. **Your    │
│    changes must be minimal and targeted, directly addressing only the   │
│    unsafe buffer errors.** While the primary focus is on the given      │
│    file, you are expected to modify other files (e.g., header files or  │
│    call sites) if necessary to ensure the code compiles and tests pass. │
│                                                                         │
│    ### **Guiding Philosophy**                                           │
│    *   **Safety Through the Type System:** The fundamental goal is to   │
│    encode buffer size information into the C++ type system. A `char*`   │
│    has no size information, making it unsafe. A `base::span<char>` has  │
│    a size, making it safe. Every change you make should serve this      │
│    principle.                                                           │
│    *   **Minimalism is Essential:** Your task is not to refactor or     │
│    improve the code in general. You are a specialist surgeon fixing one │
│     specific problem: unsafe buffer usage. Make the smallest possible   │
│    change that fixes the compiler warning and passes tests.             │
│    *   **Trust, But Verify with Compilation:** Your primary feedback    │
│    loop is the compiler. After removing the `allow_unsafe_buffers`      │
│    pragma, the `-Wunsafe-buffer-usage` errors are your map. Use them to │
│     identify every location that needs a fix.                           │
│                                                                         │
│                                                                         │
│    You must refer to these documents to ensure your solutions are       │
│    idiomatic and correct within the Chromium ecosystem.                 │
│                                                                         │
│    # Workflow Tips                                                      │
│                                                                         │
│    ## General Workflow:                                                 │
│                                                                         │
│      * **User Guidance:** Proactively communicate your plan and the     │
│    reason for each                                                      │
│        step.                                                            │
│      * **File Creation Pre-check:** Before creating any new file, you   │
│    MUST first                                                           │
│        perform a thorough search for existing files that can be         │
│    modified or                                                          │
│        extended. This is especially critical for tests; never create a  │
│    new test                                                             │
│        file if one already exists for the component in question. Always │
│     add new                                                             │
│        tests to the existing test file.                                 │
│      * **Read Before Write/Edit:** **ALWAYS** read the entire file      │
│    content                                                              │
│        immediately before writing or editing.                           │
│                                                                         │
│    ## MANDATORY DEBUGGING PROTOCOL (WHEN STUCK)                         │
│                                                                         │
│      * **Trigger:** You **MUST** activate this protocol if you          │
│    encounter a                                                          │
│        **Repeated Tool or Command Failure**.                            │
│                                                                         │
│          * **Definition of Repeated Failure:** A tool or command (e.g., │
│            `autoninja`, `autotest.py`, `git cl format`, `replace`)      │
│    fails. You apply                                                     │
│            a fix or change your approach. You run the *exact same tool  │
│    or command*                                                          │
│            again, and it fails for a **second time**.                   │
│          * **Sensitivity:** This protocol is intentionally highly       │
│    sensitive. The                                                       │
│            error message for the second failure does **NOT** need to be │
│     the same as                                                         │
│            the first. Any subsequent failure of the same tool or        │
│    command after a                                                      │
│            fix attempt is a trigger. This is to prevent "whack-a-mole"  │
│    scenarios                                                            │
│            where fixing one error simply reveals another, indicating a  │
│    deeper                                                               │
│            underlying problem.                                          │
│                                                                         │
│        *Check your history to confirm the repeated failure of the tool  │
│    or command.*                                                         │
│                                                                         │
│      * **Action:** If the trigger condition is met:                     │
│                                                                         │
│        1.  **STOP:** **DO NOT** immediately retry the *same* fix or     │
│    re-run the                                                           │
│            *same* tool or command again.                                │
│        2.  **INFORM USER:** Immediately inform the user that you are    │
│    invoking the                                                         │
│            debugging protocol because a tool or command has failed      │
│    twice in a row.                                                      │
│        3.  **REASON:** **Explicitly state** which tool or command       │
│    failed repeatedly                                                    │
│            (e.g., "`autotest` failed, I applied a fix, and it failed    │
│    again. I am                                                          │
│            now invoking the debugging protocol to analyze the root      │
│    cause.").                                                            │
│            Mentioning the specific error messages is good, but the      │
│    repeated failure                                                     │
│            is the primary trigger.                                      │
│        4.  **DEBUG:** Look closely into your own context, memory, and   │
│    traces. Give                                                         │
│            a deep analysis of why you are repeating mistakes and stuck  │
│    in a failure                                                         │
│            loop. The analysis should focus on the *root cause* of the   │
│    repeated                                                             │
│            failures, not just the most recent error message. Utilize    │
│    any tools that                                                       │
│            help with the debugging investigation.                       │
│        5.  **PROCEED:** Use the suggestions returned by the DEBUG step  │
│    to inform                                                            │
│            your next attempt at a fix. Explain the new, more            │
│    comprehensive plan to                                                │
│            the user. If the DEBUG step provides tool calls, execute     │
│    them.                                                                │
│            Otherwise, formulate a new plan based on its suggestions.    │
│                                                                         │
│    Do not use the `read_many_files` tool. Read files one at a time with │
│    `read_file`.                                                         │
│                                                                         │
│    Any time you want to use `grep -r`, use `rg` instead.                │
│                                                                         │
│    Any time you want to use `find`, use `fdfind` instead.               │
│                                                                         │
│    ## Standard Edit/Fix Workflow:                                       │
│                                                                         │
│    **IMPORTANT:** This workflow takes precedence over all other coding  │
│    instructions. Read and follow everything strictly without skipping   │
│    steps                                                                │
│    whenever code editing is involved. Any skipping requires a proactive │
│     message to                                                          │
│    the user about the reason to skip.                                   │
│                                                                         │
│    1.  **Comprehensive Code and Task Understanding (MANDATORY FIRST     │
│    STEP):** Before                                                      │
│        writing or modifying any code, you MUST perform the following    │
│    analysis to                                                          │
│        ensure comprehensive understanding of the relevant code and the  │
│    task. This                                                           │
│        is a non-negotiable prerequisite for all coding tasks.           │
│          * **a. Identify the Core Files:** Locate the files that are    │
│    most relevant                                                        │
│            to the user's request. All analysis starts from these files. │
│          * **b. Conduct a Full Audit:**                                 │
│            i. Read the full source of **EVERY** core file.              │
│            ii. For each core file, summarize the control flow and       │
│    ownership                                                            │
│            semantics. State the intended purpose of the core file.      │
│          * **c. State Your Understanding:** After completing the audit, │
│     you should                                                          │
│            briefly state the core files you have reviewed, confirming   │
│    your                                                                 │
│            understanding of the data flow and component interactions    │
│    before                                                               │
│            proposing a plan.                                            │
│          * **d. Anti-Patterns to AVOID:**                               │
│              * **NEVER** assume the behavior of a function or class     │
│    from its name                                                        │
│                or from usage in other files. **ALWAYS** read the source │
│                implementation.                                          │
│              * **ALWAYS** check at least one call-site for a function   │
│    or class to                                                          │
│                understand its usage. The context is as important as the │
│                implementation.                                          │
│    2.  **Make Change:** After a comprehensive code and task             │
│    understanding, apply                                                 │
│        the edit or write the file.                                      │
│          * When making code edits, focus **ONLY** on code edits that    │
│    directly solve                                                       │
│            the task prompted by the user.                               │
│    3.  **Write/Update Tests:**                                          │
│          * First, search for existing tests related to the modified     │
│    code and update                                                      │
│            them as needed to reflect the changes.                       │
│          * If no relevant tests exist, write new unit tests or          │
│    integration tests if                                                 │
│            it's reasonable and beneficial for the change made.          │
│          * If tests are deemed not applicable for a specific change     │
│    (e.g., a                                                             │
│            trivial comment update), explicitly state this and the       │
│    reason why before                                                    │
│            moving to the next step.                                     │
│    4.  **Build:** **ALWAYS** build relevant targets after making edits. │
│     Use build directory `out/Default`.                                  │
│    5.  **Fix compile errors:** **ALWAYS** follow these steps to fix     │
│    compile errors.                                                      │
│          * **ALWAYS** take the time to fully understand the problem     │
│    before making                                                        │
│            any fixes.                                                   │
│          * **ALWAYS** read at least one new file for each compile       │
│    error.                                                               │
│          * **ALWAYS** find, read, and understand **ALL** files related  │
│    to each                                                              │
│            compile error. For example, if an error is related to a      │
│    missing member                                                       │
│            of a class, find the file that defines the interface for the │
│     class, read                                                         │
│            the whole file, and then create a high-level summary of the  │
│    file that                                                            │
│            outlines all core concepts. Come up with a plan to fix the   │
│    error.                                                               │
│          * **ALWAYS** check the conversation history to see if this     │
│    same                                                                 │
│            error occurred earlier, and analyze previous solutions to    │
│    see why they                                                         │
│            didn't work.                                                 │
│          * **NEVER** make speculative fixes. You should be confident    │
│    before                                                               │
│            applying any fix that it will work. If you are not           │
│    confident, read more                                                 │
│            files.                                                       │
│    6.  **Test:** **ALWAYS** run relevant tests after a successful       │
│    build. If you                                                        │
│        cannot find any relevant test files, you may prompt the user to  │
│    ask how this                                                         │
│        change should be tested.                                         │
│    7.  **Fix test errors**:                                             │
│        * **ALWAYS** take the time to fully understand the problem       │
│    before making                                                        │
│          any fixes.                                                     │
│    8.  **Iterate:** Repeat building and testing using the above steps   │
│    until all are                                                        │
│        successful.                                                      │
│                                                                         │
│    ---                                                                  │
│                                                                         │
│    ### **Core Principles for Safe Buffer Handling**                     │
│                                                                         │
│    Before looking at specific patterns, adhere to these fundamental     │
│    principles.                                                          │
│                                                                         │
│    *   **Principle 0: Clearly Distinguish Ownership**                   │
│        Before you change any code, your first step is to determine if   │
│    the variable in question represents owning or non-owning memory.     │
│    This single decision dictates the correct C++ type to use.           │
│                                                                         │
│        *   **Owning Buffers:** Use an owning container when the code is │
│     responsible for the memory's lifetime (allocating and freeing it).  │
│            *   `std::vector<T>`: This is the default and preferred      │
│    choice for a dynamically-sized, owning buffer.                       │
│            *   `std::string`: The standard choice for owning a buffer   │
│    of characters.                                                       │
│            *   `std::array<T, N>`: Use this for a fixed-size buffer     │
│    whose lifetime is tied to its scope (typically on the stack). It's a │
│     direct, safer replacement for C-style arrays like `int              │
│    my_array[10];`.                                                      │
│            *   `base::HeapArray<T>`: A Chromium-specific alternative    │
│    for heap-allocated arrays, sometimes useful for interfacing with     │
│    legacy code.                                                         │
│                                                                         │
│        *   **Non-Owning Buffers (Views/Spans):** Use a non-owning view  │
│    when the code needs to safely refer to and operate on memory that is │
│     owned by another object (like a `std::vector` or `std::array`).     │
│            *   `base::span<T>`: This is the default and preferred       │
│    choice for a non-owning, mutable, or immutable view of a contiguous  │
│    sequence of objects. It's the primary tool for replacing `(T* ptr,   │
│    size_t size)` parameters.                                            │
│            *   `std::string_view`: Use this for a non-owning, read-only │
│     view of a sequence of characters. It provides a rich set of         │
│    string-manipulation methods (`.starts_with()`, `.find()`, etc.) that │
│     `base::span<const char>` lacks.                                     │
│                                                                         │
│    *   **Principle 1: Avoid Unsafe APIs, Even If They Look Modern.**    │
│    The goal is to eliminate the *root cause* of unsafety, not just      │
│    silence the compiler. Certain modern-looking APIs are still unsafe.  │
│                                                                         │
│        *   **DO NOT USE:** The `base::span(pointer, size)` constructor. │
│     It is marked `UNSAFE_BUFFER_USAGE` for a reason—it does not verify  │
│    that `size` is a valid length for `pointer`. Using it is no safer    │
│    than the original code.                                              │
│        *   **DO NOT USE:** `std::next()` or `std::advance()` to silence │
│     buffer warnings. These functions perform unchecked pointer          │
│    arithmetic and are just as unsafe as `ptr + offset`.                 │
│            ```cpp                                                       │
│            // Old and Unsafe (silences warning, but still dangerous):   │
│            auto it = std::find(std::next(vec.begin(), offset),          │
│    vec.end(), 20);                                                      │
│            // New and Safe:                                             │
│            auto it = std::ranges::find(base::span(vec).subspan(offset), │
│     20);                                                                │
│            ```                                                          │
│        *   **DO NOT USE:** `base::StringView`. This is a legacy,        │
│    deprecated type. The correct and modern type for a non-owning string │
│     view is `std::string_view`. Be mindful to use the `std` namespace   │
│    for string views.                                                    │
│        *   **DO NOT USE: `UNSAFE_BUFFERS` without a safety              │
│    justification.** Individual expressions can be opted out with        │
│    `UNSAFE_BUFFERS()`, but these are for rare cases like interfacing    │
│    with C-style external APIs. They **must always** be accompanied by a │
│     `// SAFETY:` comment explaining in detail why the code has been     │
│    evaluated to be safe for all possible inputs. Code without this      │
│    justification should be rejected.                                    │
│                                                                         │
│    *   **Principle 3: Prefer Safe, Size-Aware Constructors and          │
│    Factories.** Always create spans from sources that already know      │
│    their own size. This is the key to memory safety.                    │
│                                                                         │
│        *   **DO USE:** `base::span(container)` where `container` is an  │
│    `std::vector`, `std::array`, `std::string`, `base::HeapArray`, etc.  │
│        *   **DO USE:** `base::span(other_span).subspan(...)` to create  │
│    safe views into existing spans.                                      │
│        *   **DO USE:** `base::as_byte_span(container)` and              │
│    `base::as_writable_byte_span(container)` for safe type-punning to a  │
│    byte view.                                                           │
│        *   **DO USE:** `base::span_from_ref(object)` to create a span   │
│    of size 1 pointing to a single object.                               │
│        *   **DO USE:** `base::byte_span_from_ref(object)` for a byte    │
│    view of a single object.                                             │
│                                                                         │
│    ---                                                                  │
│                                                                         │
│    ### **Toolbox of Fixes and Patterns**                                │
│                                                                         │
│    Here is a comprehensive set of patterns for fixing common unsafe     │
│    buffer issues.                                                       │
│                                                                         │
│    #### **1. Fundamental Replacements: Pointers and C-Arrays**          │
│                                                                         │
│    The most common task is replacing raw pointers and C-style arrays    │
│    with safer, bounds-checked alternatives.                             │
│                                                                         │
│    *   **Pattern:** Replace function parameters `(T* ptr, size_t size)` │
│     with a single `base::span<T>`.                                      │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            void ProcessData(const uint8_t* data, size_t size);          │
│                                                                         │
│            // New                                                       │
│            void ProcessData(base::span<const uint8_t> data);            │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** Replace C-style stack arrays `T arr[N]` with        │
│    `std::array<T, N>`. For string literals, `std::to_array` is a        │
│    convenient helper.                                                   │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            const char kAllowed[] = "abc";                               │
│            int values[10];                                              │
│                                                                         │
│            // New                                                       │
│            // For C-style string literals, std::to_array is simplest.   │
│            constexpr auto kAllowed = std::to_array("abc");              │
│            std::array<int, 10> values;                                  │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** Replace raw heap-allocated arrays (`new T[size]`,   │
│    `std::make_unique<T[]>(size)`) with `std::vector<T>` or              │
│    `base::HeapArray<T>`.                                                │
│                                                                         │
│        *   **Reasoning:** `std::vector` and `base::HeapArray` are       │
│    self-managing, provide size information, and prevent common memory   │
│    management errors. They also integrate perfectly with `base::span`.  │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            auto buffer = std::make_unique<char[]>(1024);                │
│            ReadData(fd, buffer.get(), 1024);                            │
│                                                                         │
│            // New                                                       │
│            std::vector<char> buffer(1024);                              │
│            ReadData(fd, base::as_writable_byte_span(buffer));           │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** When passing an array to a function, use            │
│    `base::span` to create a non-owning view.                            │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            std::array<int, 10> my_array;                                │
│            // Old: ProcessData(my_array.data(), my_array.size());       │
│            // New                                                       │
│            ProcessData(base::span(my_array));                           │
│            ```                                                          │
│    *   **Pattern:** For class member fields that are non-owning views,  │
│    you must use `base::raw_span<T>` over `base::span<T>`.               │
│        *   **Reasoning:** This is a critical memory safety requirement. │
│     `base::raw_span` is implemented with MiraclePtr, which protects     │
│    against Use-After-Free (UAF) bugs. If the underlying object is       │
│    freed, any attempt to use the `raw_span` will result in a controlled │
│     crash instead of allowing dangerous memory corruption or type       │
│    confusion attacks. A regular `base::span` offers no UAF protection.  │
│        ```cpp                                                           │
│        class MyClass {                                                  │
│         private:                                                        │
│          // Old: base::span<int> data_;                                 │
│          // New:                                                        │
│          base::raw_span<int> data_;                                     │
│        };                                                               │
│        ```                                                              │
│                                                                         │
│    #### **2. Replacing Unsafe C-Style Library Functions**               │
│                                                                         │
│    *   **Pattern:** Replace `memcpy` and `memmove` with                 │
│    `base::span::copy_from()`.                                           │
│        *   **Reasoning:** Do not use `std::ranges::copy`. It is unsafe  │
│    because it does not verify that the source and destination spans     │
│    have the same size, which can lead to buffer overflows.              │
│    `base::span::copy_from()` is the only safe alternative, as it        │
│    includes a `CHECK` to ensure the sizes match exactly.                │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            memcpy(dest_ptr, src_ptr, N);                                │
│                                                                         │
│            // New (Safe and Idiomatic)                                  │
│            // This CHECKs that both subspans are of size N.             │
│            dest_span.first(N).copy_from(src_span.first(N));             │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** Replace `memset` with `std::ranges::fill()`.        │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            memset(buffer, 0, sizeof(buffer));                           │
│                                                                         │
│            // New                                                       │
│            std::ranges::fill(my_span, 0);                               │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** Replace `memcmp` with `base::span::operator==` or   │
│    `std::ranges::equal`.                                                │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            bool are_equal = memcmp(ptr1, ptr2, size) == 0;              │
│                                                                         │
│            // New                                                       │
│            bool are_equal = span1 == span2;                             │
│            ```                                                          │
│                                                                         │
│    #### **3. Eliminating Pointer Arithmetic and Unsafe Casting**        │
│                                                                         │
│    *   **Pattern:** Replace pointer arithmetic like `ptr + offset` with │
│     `span.subspan(offset)`.                                             │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            ProcessData(data + 10, size - 10);                           │
│                                                                         │
│            // New                                                       │
│            ProcessData(data_span.subspan(10));                          │
│            ```                                                          │
│                                                                         │
│    *   **Pattern:** Avoid `reinterpret_cast` for changing element       │
│    types. Use safe casting functions like `base::as_bytes()`,           │
│    `base::as_writable_byte_span()`, or `base::as_chars()`.              │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            const uint8_t* bytes = reinterpret_cast<const                │
│    uint8_t*>(str.data());                                               │
│                                                                         │
│            // New                                                       │
│            base::span<const uint8_t> bytes = base::as_byte_span(str);   │
│            ```                                                          │
│        *   **Caution:** When using `base::as_byte_span()` on a          │
│    `struct`, be aware of padding bytes. If the struct's padding is not  │
│    explicitly initialized (e.g., via `memset` or aggregate              │
│    initialization), reading from the resulting byte span can lead to    │
│    reads of uninitialized memory. This is safest with spans of          │
│    primitive types.                                                     │
│                                                                         │
│    *   **Pattern:** To read or write structured data (like a            │
│    `uint32_t`) from/to a byte buffer, use the endian-converting helpers │
│     from `base/numerics/byte_conversions.h`.                            │
│                                                                         │
│        *   **Example (Writing):**                                       │
│            ```cpp                                                       │
│            // Old (UNSAFE AND UNDEFINED BEHAVIOR)                       │
│            *reinterpret_cast<uint32_t*>(byte_span.data()) = my_value;   │
│                                                                         │
│            // New (Safe and Idiomatic)                                  │
│            #include "base/numerics/byte_conversions.h"                  │
│            auto value_bytes = base::U32ToLittleEndian(my_value);        │
│            byte_span.first(value_bytes.size()).copy_from(value_bytes);  │
│            ```                                                          │
│                                                                         │
│        *   **Example (Reading):**                                       │
│            ```cpp                                                       │
│            // Old (UNSAFE)                                              │
│            uint32_t value = *reinterpret_cast<const                     │
│    uint32_t*>(byte_span.data());                                        │
│                                                                         │
│            // New (Safe and Idiomatic)                                  │
│            #include "base/numerics/byte_conversions.h"                  │
│            uint32_t value =                                             │
│    base::U32FromLittleEndian(byte_span.first<4>());                     │
│            ```                                                          │
│    *   **Pattern:** For dynamic or heterogeneous I/O, use               │
│    `base::SpanReader` and `base::SpanWriter` to safely consume or       │
│    populate a buffer. This is safer and more expressive than manual     │
│    pointer casting and offsetting.                                      │
│        * **Example (Writing with `SpanWriter`):**                       │
│          ```cpp                                                         │
│          #include "base/containers/span_writer.h"                       │
│          #include "base/numerics/byte_conversions.h"                    │
│          void WriteData(base::span<uint8_t> out, uint32_t id, float     │
│    value) {                                                             │
│            auto writer = base::SpanWriter(out);                         │
│            writer.WriteU32BigEndian(id);                                │
│            writer.Write(base::FloatToLittleEndian(value));              │
│          }                                                              │
│          ```                                                            │
│    *   **Pattern:** Refactor sequential buffer filling with a           │
│    "consuming span". This is for cases where a buffer is allocated      │
│    once, and then a pointer is manually advanced as data is written to  │
│    it sequentially.                                                     │
│        *   **Reasoning:** Instead of managing a write-pointer and an    │
│    end-pointer manually, a single `base::span` can represent the        │
│    remaining, writable portion of the buffer. This is safer and more    │
│    expressive.                                                          │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Helper function that writes a string and "consumes" part  │
│    of the span.                                                         │
│            void WriteStringAndAdvance(base::span<char>& buffer, const   │
│    char* str) {                                                         │
│              if (!str) {                                                │
│                return;                                                  │
│              }                                                          │
│              const size_t len_with_null = strlen(str) + 1;              │
│              DCHECK_GE(buffer.size(), len_with_null);                   │
│              memcpy(buffer.data(), str, len_with_null);                 │
│              // The span is sliced, now pointing to the remaining       │
│    writable area.                                                       │
│              buffer = buffer.subspan(len_with_null);                    │
│            }                                                            │
│                                                                         │
│            // Old function that manually manages pointers.              │
│            void CreateMessageUnsafe(char* buffer, size_t size, const    │
│    char* str1, const char* str2) {                                      │
│                char* ptr = buffer;                                      │
│                const char* end = buffer + size;                         │
│                                                                         │
│                // Manual copy and advance                               │
│                size_t len1 = strlen(str1) + 1;                          │
│                CHECK_LE(ptr + len1, end);                               │
│                memcpy(ptr, str1, len1);                                 │
│                ptr += len1;                                             │
│                                                                         │
│                // Another manual copy and advance                       │
│                size_t len2 = strlen(str2) + 1;                          │
│                CHECK_LE(ptr + len2, end);                               │
│                memcpy(ptr, str2, len2);                                 │
│                ptr += len2;                                             │
│            }                                                            │
│                                                                         │
│            // New function using the "consuming span" pattern.          │
│            void CreateMessageSafe(base::span<char> buffer, const char*  │
│    str1, const char* str2) {                                            │
│                WriteStringAndAdvance(buffer, str1);                     │
│                WriteStringAndAdvance(buffer, str2);                     │
│                // At this point, `buffer` correctly represents the      │
│    unused portion.                                                      │
│            }                                                            │
│            ```                                                          │
│        *   **Key Idea:** The core of this pattern is to create a helper │
│     function (like `WriteStringAndAdvance`) that takes the main buffer  │
│    span by reference (`&`). The helper writes its data and then         │
│    reassigns the span to a smaller subspan, effectively advancing the   │
│    "write position" for the next operation in the calling function.     │
│                                                                         │
│    #### **4. String and Character Manipulation**                        │
│                                                                         │
│    *   **Pattern:** Replace C-style string literals (`const char        │
│    kFoo[]`) with `constexpr std::string_view kFoo` or `constexpr        │
│    std::array`.                                                         │
│    *   **Pattern:** For C APIs that require a NUL-terminated string,    │
│    use `base::cstring_view`.                                            │
│    *   **Pattern:** Replace C-style string functions (`strcmp`,         │
│    `strstr`, etc.) with `std::string_view` methods (`operator==`,       │
│    `.find()`, etc.).                                                    │
│    *   **Pattern:** Replace pointer-based iteration over a buffer with  │
│    a range-based for loop over a `base::span`.                          │
│    *   **Pattern:** Choose the correct string view type based on        │
│    null-termination requirements.                                       │
│        *   **Reasoning:** You must differentiate between internal C++   │
│    logic and calls to C-style APIs. A `std::string_view` is not         │
│    guaranteed to be null-terminated, while `base::cstring_view`         │
│    provides this guarantee. Using the wrong type can lead to buffer     │
│    over-reads.                                                          │
│        *   **Decision Flow:**                                           │
│            *   If the string is only used with modern C++ methods (like │
│     `.find()` or range `for` loops) that use an explicit size, use      │
│    `std::string_view`.                                                  │
│            *   If the string needs to be passed to an API that requires │
│     a null-terminated `const char*` (like `printf`, `sscanf`, or legacy │
│     functions), you must use `base::cstring_view`.                      │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // A legacy C-style function                                 │
│            void LogToOldSystem(const char* message);                    │
│                                                                         │
│            // ---                                                       │
│            // In some calling code ---                                  │
│            std::string my_string = "Hello, World!";                     │
│            std::string_view full_view = my_string;                      │
│                                                                         │
│            // UNSAFE: This substring is not null-terminated in          │
│    my_string.                                                           │
│            std::string_view unsafe_view = full_view.substr(7, 5); //    │
│    "World"                                                              │
│            // LogToOldSystem(unsafe_view.data()); // BUG! Reads past    │
│    "d" into garbage.                                                    │
│                                                                         │
│            // SAFE: Create a new std::string which is guaranteed to be  │
│    null-terminated.                                                     │
│            std::string safe_string(unsafe_view);                        │
│            LogToOldSystem(safe_string.c_str());                         │
│                                                                         │
│            // IDEAL: Use a type that enforces the contract.             │
│            // If the source is already a C-string, cstring_view is      │
│    zero-copy.                                                           │
│            base::cstring_view safe_c_view = "Hello, World!";            │
│            LogToOldSystem(safe_c_view.c_str());                         │
│            ```                                                          │
│                                                                         │
│                                                                         │
│    #### **5. Advanced Patterns**                                        │
│    *   **Pattern:** To get a heap-allocated buffer with a specific      │
│    memory alignment, use `base::AlignedUninit<T>` from                  │
│    `base/memory/aligned_memory.h`.                                      │
│        ```cpp                                                           │
│        #include "base/memory/aligned_memory.h"                          │
│        // Get an uninitialized array of 16 floats, aligned to 32 bytes. │
│        base::AlignedHeapArray<float> array =                            │
│    base::AlignedUninit<float>(16, 32);                                  │
│        ```                                                              │
│                                                                         │
│    #### **6. Common Chromium-Specific Patterns**                        │
│                                                                         │
│    *   **`net::IOBuffer`:** This class and its subclasses               │
│    (`IOBufferWithSize`, `VectorIOBuffer`) now have span-like methods.   │
│    Use them.                                                            │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            auto data_view = base::span(                                 │
│                reinterpret_cast<const uint8_t*>(io_buffer->data()),     │
│    data_len);                                                           │
│                                                                         │
│            // New                                                       │
│            auto data_view = io_buffer->first(data_len);                 │
│            ```                                                          │
│                                                                         │
│    *   **`net::VectorIOBuffer`:** To create a buffer with known         │
│    content, prefer constructing a `net::VectorIOBuffer` directly from a │
│     `std::vector` or `base::span` instead of allocating a raw buffer    │
│    and using `memcpy`.                                                  │
│                                                                         │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            auto buffer =                                                │
│    base::MakeRefCounted<net::IOBufferWithSize>(data.size());            │
│            memcpy(buffer->data(), data.data(), data.size());            │
│                                                                         │
│            // New                                                       │
│            auto buffer =                                                │
│    base::MakeRefCounted<net::VectorIOBuffer>(data);                     │
│            ```                                                          │
│                                                                         │
│    #### **7. Interfacing with C-style/Third-Party APIs**                │
│                                                                         │
│    *   **Pattern:** When a C API returns pointers to different memory   │
│    planes (e.g., video frames), create `base::span`s from those         │
│    pointers and their known sizes at the API boundary. Use              │
│    `UNSAFE_BUFFERS()` for this initial creation, then pass the safe     │
│    spans throughout the rest of your C++ code.                          │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old                                                       │
│            uint8_t* y_ptr = vpx_image->planes[0];                       │
│            uint8_t* u_ptr = vpx_image->planes[1];                       │
│            VideoFrame::WrapExternalYuvData(..., y_ptr, u_ptr, ...);     │
│                                                                         │
│            // New                                                       │
│            // SAFETY: libvpx guarantees these pointers and sizes are    │
│    valid.                                                               │
│            auto y_plane =                                               │
│    UNSAFE_BUFFERS(base::span(vpx_image->planes[0], y_size));            │
│            auto u_plane =                                               │
│    UNSAFE_BUFFERS(base::span(vpx_image->planes[1], u_size));            │
│            VideoFrame::WrapExternalYuvData(..., y_plane, u_plane, ...); │
│            ```                                                          │
│                                                                         │
│    #### **8. The Containment Strategy: When a Full Fix is Too Complex** │
│                                                                         │
│    Sometimes, a complete refactor is not immediately feasible. In these │
│     cases, contain the unsafe operations.                               │
│                                                                         │
│    *   **Strategy:** Instead of a file-level `#pragma`, wrap the        │
│    *minimal* number of unsafe operations in the `UNSAFE_TODO()` macro.  │
│    This macro acts like `UNSAFE_BUFFERS()` but signals that the code is │
│     a candidate for a future fix.                                       │
│    *   **Function-level Annotation:** If a function contains            │
│    `UNSAFE_TODO()`, you must also mark the function's signature with    │
│    the `UNSAFE_BUFFER_USAGE` attribute. This propagates the unsafety    │
│    requirement to its callers, ensuring they are also marked or within  │
│    an unsafe block.                                                     │
│        *   **Example:**                                                 │
│            ```cpp                                                       │
│            // Old:                                                      │
│            // #pragma allow_unsafe_buffers                              │
│            // void DoSomething(const char* p) {                         │
│            //   p++;                                                    │
│            // }                                                         │
│                                                                         │
│            // New (Contained):                                          │
│            UNSAFE_BUFFER_USAGE void DoSomething(const char* p) {        │
│              UNSAFE_TODO(p++);                                          │
│            }                                                            │
│            ```                                                          │
│                                                                         │
│    #### **9. Handling Redundant Parameters**                            │
│                                                                         │
│    *   **Identify redundant parameters:** In functions that now take a  │
│    base::span, find any size parameters that are now unneeded. A        │
│    parameter is still considered redundant even if it's already used in │
│     a CHECK or DCHECK.                                                  │
│                                                                         │
│    *   **Rename the parameter:** For any redundant parameter, rename it │
│     and all its references within the function by adding the prefix     │
│    spanification_suspected_redundant_.                                  │
│                                                                         │
│    *   **Add a TODO and a CHECK:** At the top of the function body, add │
│     the following two lines:                                            │
│                                                                         │
│        *   A TODO comment:                                              │
│            ```cpp                                                       │
│            // TODO(crbug.com/431824301): Remove unneeded parameter once │
│     validated to be redundant in M143.                                  │
│            ```                                                          │
│        *   A CHECK to verify the redundant parameter matches the span's │
│     size:                                                               │
│            ```cpp                                                       │
│            CHECK(spanification_suspected_redundant_size_variable ==     │
│    span.size(), base::NotFatalUntil::M143);                             │
│            ```                                                          │
│                                                                         │
│    *   **Customize the CHECK:** In the CHECK you just added, you must:  │
│                                                                         │
│        *   Replace spanification_suspected_redundant_size_variable with │
│     the new name of the parameter you renamed in step 2.                │
│                                                                         │
│        *   Replace span.size() with a call to the actual base::span     │
│    parameter's .size() method.                                          │
│                                                                         │
│    *   **Important constraints:**                                       │
│                                                                         │
│        *   Do not remove the parameter or update any call sites.        │
│                                                                         │
│        *   Do not change the function's logic to use span.size();       │
│    continue to use the newly-renamed parameter variable.                │
│                                                                         │
│        *   Do ensure the size parameter and the base::span's size are   │
│    in the same unit before making changes.                              │
│                                                                         │
│        *   Do not remove the parameter or the CHECK even if you         │
│    confirmed that the unit tests pass.                                  │
│                                                                         │
│    #### **10. Updating Function Definitions and Call Sites**            │
│                                                                         │
│    *   **Updating the Function Definition**                             │
│        *   **Identify the target function:** Look for functions that    │
│    have a parameter with the name pattern                               │
│    spanification_suspected_redundant_....                               │
│        *   **Remove the parameter:** In the function's definition and   │
│    any corresponding declarations (e.g., in a header file), completely  │
│    remove the redundant size parameter from the parameter list.         │
│        *   **Replace internal usages:** Inside the function's body,     │
│    replace every use of the removed parameter with a call to the        │
│    base::span's .size() method (e.g., my_span.size()).                  │
│                                                                         │
│    *   **Updating the Call Sites**                                      │
│        *   **Find all call sites:** Use a command like git grep with    │
│    the function name to find every location where the function is       │
│    called throughout the codebase.                                      │
│        *   **Remove the argument at each call site:** For each call     │
│    site you find, you must remove the argument that corresponds to the  │
│    size parameter you deleted from the function's definition.           │
│        *   **Important:** Be very careful to only remove the specific,  │
│    redundant argument. Do not change or remove any other arguments in   │
│    the function call.                                                   │
│                                                                         │
│    *   **Key Constraints**                                              │
│        *   You should only remove the parameter previously marked as    │
│    redundant and its corresponding arguments at call sites.             │
│        *   Do not remove or rename any other parameters.                │
│        *   Do not rewrite the function's logic beyond replacing the     │
│    deleted variable with span.size().                                   │
│        *   Ensure that when you update a call site, you only remove the │
│     single, correct argument.                                           │
│                                                                         │
│    #### **11. Handling Autogenerated Files**                            │
│                                                                         │
│    *   **Pattern:** Another common pattern is for a change to require   │
│    modification to an autogenerated file. Treat autogenerated files as  │
│    unmodifiable for now.                                                │
│    ---                                                                  │
│    #### **12. Wrapping Unsafe APIs with Macros**                        │
│                                                                         │
│    In some cases, you will encounter functions from third-party         │
│    libraries or other unmodifiable parts of the codebase that return a  │
│    raw pointer to a buffer. Directly wrapping these with                │
│    `UNSAFE_BUFFERS(base::span(pointer, size))` is one option, but a     │
│    more robust and reusable solution is to create a dedicated wrapper   │
│    macro in `base/containers/auto_spanification_helper.h`.              │
│                                                                         │
│    *   **Strategy:** When an unmodifiable function call returns a raw   │
│    pointer instead of a safe container like `base::span`, follow this   │
│    procedure:                                                           │
│        1.  **Check for an existing macro:** First, examine              │
│    `base/containers/auto_spanification_helper.h` to see if a macro for  │
│    this specific API call already exists.                               │
│        2.  **Create a new macro if needed:** If no macro exists, you    │
│    must add one.                                                        │
│            *   The macro should be added to                             │
│    `base/containers/auto_spanification_helper.h`.                       │
│            *   The macro should take the same arguments as the original │
│     API call.                                                           │
│            *   Inside the macro, call the original API, get the pointer │
│     and size, and return a `base::span`. Use `UNSAFE_TODO` to wrap the  │
│    returned span.                                                       │
│            *   Follow the existing macro patterns in the file, using a  │
│    lambda to avoid multiple argument evaluation.                        │
│        3.  **Add a test for the new macro:** You must add a new test    │
│    case to `base/containers/auto_spanification_helper_unittest.cc`.     │
│            *   The test should mock the third-party API and verify that │
│     the macro correctly creates a `base::span` with the expected data   │
│    and size.                                                            │
│        4.  **Use the macro:** Replace the original unsafe API call in   │
│    your target file with the new or existing macro.                     │
│                                                                         │
│    *   **Example: Adding a macro for `SkBitmap::getAddr32`**            │
│                                                                         │
│        *   **Macro in `auto_spanification_helper.h`:**                  │
│            ```cpp                                                       │
│            // https://source.chromium.org/chromium/chromium/src/+/main: │
│    third_party/skia/include/core/SkBitmap.h;drc=f72bd467feb15edd9323e46 │
│    eab1b74ab6025bc5b;l=936                                              │
│            #define UNSAFE_SKBITMAP_GETADDR32(arg_self, arg_x, arg_y) \  │
│              ([](auto&& self, int x, int y) {                        \  │
│                uint32_t* row = self->getAddr32(x, y);                \  │
│                ::base::CheckedNumeric<size_t> width = self->width(); \  │
│                size_t size = (width - x).ValueOrDie();               \  │
│                return UNSAFE_TODO(base::span<uint32_t>(row, size));  \  │
│              }(::base::spanification_internal::ToPointer(arg_self),     │
│    arg_x, arg_y))                                                       │
│            ```                                                          │
│                                                                         │
│        *   **Test in `auto_spanification_helper_unittest.cc`:**         │
│            ```cpp                                                       │
│            // Minimized mock of SkBitmap class defined in               │
│            // //third_party/skia/include/core/SkBitmap.h                │
│            class SkBitmap {                                             │
│             public:                                                     │
│              uint32_t* getAddr32(int x, int y) const { return &row_[x]; │
│     }                                                                   │
│              int width() const { return static_cast<int>(row_.size());  │
│    }                                                                    │
│                                                                         │
│              mutable std::array<uint32_t, 128> row_{};                  │
│            };                                                           │
│                                                                         │
│            TEST(AutoSpanificationHelperTest, SkBitmapGetAddr32Pointer)  │
│    {                                                                    │
│              SkBitmap sk_bitmap;                                        │
│              const int x = 123;                                         │
│              base::span<uint32_t> span =                                │
│    UNSAFE_SKBITMAP_GETADDR32(&sk_bitmap, x, 0);                         │
│              EXPECT_EQ(span.data(), &sk_bitmap.row_[x]);                │
│              EXPECT_EQ(span.size(), sk_bitmap.row_.size() - x);         │
│            }                                                            │
│            ```                                                          │
│    ---                                                                  │
│                                                                         │
│    Pattern: Refactor sequential buffer filling with a "consuming span". │
│     This is for cases where a buffer is allocated once, and then a      │
│    pointer is manually advanced as data is written to it sequentially.  │
│                                                                         │
│    Reasoning: Instead of managing a write-pointer and an end-pointer    │
│    manually, a single base::span can represent the remaining, writable  │
│    portion of the buffer. This is safer and more expressive.            │
│                                                                         │
│    Example:                                                             │
│                                                                         │
│    C++                                                                  │
│                                                                         │
│    ---                                                                  │
│    // Helper function that writes a string and "consumes" part of the   │
│    span.                                                                │
│    void WriteStringAndAdvance(base::span<char>& buffer, const char*     │
│    str) {                                                               │
│      if (!str) {                                                        │
│        return;                                                          │
│      }                                                                  │
│      const size_t len_with_null = strlen(str) + 1;                      │
│      DCHECK_GE(buffer.size(), len_with_null);                           │
│      memcpy(buffer.data(), str, len_with_null);                         │
│      // The span is sliced, now pointing to the remaining writable      │
│    area.                                                                │
│      buffer = buffer.subspan(len_with_null);                            │
│    }                                                                    │
│                                                                         │
│    // Old function that manually manages pointers.                      │
│    void CreateMessageUnsafe(char* buffer, size_t size, const char*      │
│    str1, const char* str2) {                                            │
│        char* ptr = buffer;                                              │
│        const char* end = buffer + size;                                 │
│                                                                         │
│        // Manual copy and advance                                       │
│        size_t len1 = strlen(str1) + 1;                                  │
│        CHECK_LE(ptr + len1, end);                                       │
│        memcpy(ptr, str1, len1);                                         │
│        ptr += len1;                                                     │
│                                                                         │
│        // Another manual copy and advance                               │
│        size_t len2 = strlen(str2) + 1;                                  │
│        CHECK_LE(ptr + len2, end);                                       │
│        memcpy(ptr, str2, len2);                                         │
│        ptr += len2;                                                     │
│    }                                                                    │
│                                                                         │
│    // New function using the "consuming span" pattern.                  │
│    void CreateMessageSafe(base::span<char> buffer, const char* str1,    │
│    const char* str2) {                                                  │
│        WriteStringAndAdvance(buffer, str1);                             │
│        WriteStringAndAdvance(buffer, str2);                             │
│        // At this point, `buffer` correctly represents the unused       │
│    portion.                                                             │
│    }                                                                    │
│    Key Idea: The core of this pattern is to create a helper function    │
│    (like WriteStringAndAdvance) that takes the main buffer span by      │
│    reference (&). The helper writes its data and then reassigns the     │
│    span to a smaller subspan, effectively advancing the "write          │
│    position" for the next operation in the calling function.            │
│    ---                                                                  │
╰──────────────────────────────────────────────────────────────────────────╯





























✦ Okay, I will finish the patch to spanify
  media/filters/ffmpeg_aac_bitstream_converter.cc. First, I'll examine the
   current patch.
 ╭──────────────────────────────────────────────────────╮
 │ ✔  Shell git show HEAD (Examine the current patch.)  │
 │                                                      │
 │    commit                                            │
 │    b1a2d8ea849a343ade4cb7511c8ede07e466f57           │
 │    6                                                 │
 │    Author: Keishi Hattori                            │
 │    <keishi@chromium.org>                             │
 │    Date:   Tue Aug 19 03:34:22 2025 +0000            │
 │                                                      │
 │        Apply initial patch from                      │
 │    group_139.txt                                     │
 │                                                      │
 │    diff --git                                        │
 │    a/media/filters/ffmpeg_aac_bitstream_co           │
 │    nverter.cc                                        │
 │    b/media/filters/ffmpeg_aac_bitstream_co           │
 │    nverter.cc                                        │
 │    index c00ac262dabb1..14f692ebc0d24                │
 │    100644                                            │
 │    ---                                               │
 │    a/media/filters/ffmpeg_aac_bitstream_co           │
 │    nverter.cc                                        │
 │    +++                                               │
 │    b/media/filters/ffmpeg_aac_bitstream_co           │
 │    nverter.cc                                        │
 │    @@ -2,6 +2,8 @@                                   │
 │     // Use of this source code is governed           │
 │    by a BSD-style license that can be                │
 │     // found in the LICENSE file.                    │
 │                                                      │
 │    +#include "base/containers/span.h"                │
 │    +                                                 │
 │     #ifdef UNSAFE_BUFFERS_BUILD                      │
 │     // TODO(crbug.com/40285824): Remove              │
 │    this and convert code to safer                    │
 │    constructs.                                       │
 │     #pragma allow_unsafe_buffers                     │
 │    @@ -32,10 +34,10 @@ bool                          │
 │    GenerateAdtsHeader(int codec,                     │
 │                             int                      │
 │    frame_length,                                     │
 │                             int                      │
 │    buffer_fullness,                                  │
 │                             int                      │
 │    number_of_frames_minus_one,                       │
 │    -                        uint8_t* hdr)            │
 │    {                                                 │
 │    +                                                 │
 │    base::span<uint8_t>hdr) {                         │
 │       DCHECK_EQ(codec, AV_CODEC_ID_AAC);             │
 │                                                      │
 │    -  memset(reinterpret_cast<void                   │
 │    *>(hdr), 0,                                       │
 │    +  memset(reinterpret_cast<void                   │
 │    *>(hdr.data()), 0,                                │
 │                                                      │
 │    FFmpegAACBitstreamConverter::kAdtsHeade           │
 │    rSize);                                           │
 │       // Ref:                                        │
 │    http://wiki.multimedia.cx/index.php?tit           │
 │    le=ADTS                                           │
 │       // ADTS header structure is the                │
 │    following                                         │
 │    @@ -233,7 +235,7 @@ bool                          │
 │    FFmpegAACBitstreamConverter::ConvertPac           │
 │    ket(AVPacket* packet) {                           │
 │       if (av_new_packet(&dest_packet,                │
 │    header_plus_packet_size) != 0)                    │
 │         return false;  // Memory                     │
 │    allocation failure.                               │
 │                                                      │
 │    -  memcpy(dest_packet.data, hdr_,                 │
 │    kAdtsHeaderSize);                                 │
 │    +  memcpy(dest_packet.data,                       │
 │    hdr_.data(), kAdtsHeaderSize);                    │
 │                                                      │
 │    memcpy(reinterpret_cast<void*>(dest_pac           │
 │    ket.data + kAdtsHeaderSize),                      │
 │                                                      │
 │    reinterpret_cast<void*>(packet->data),            │
 │    packet->size);                                    │
 │                                                      │
 │                                                      │
 ╰──────────────────────────────────────────────────────╯
✦ The initial patch is a good start, but I need to replace the memset and
  memcpy calls with safer alternatives. My plan is to read
  media/filters/ffmpeg_aac_bitstream_converter.cc, remove the
  allow_unsafe_buffers pragma, and then compile media_filters to find the
  unsafe buffer usage. I'll then fix the errors using std::ranges::fill
  and base::span::copy_from, rebuild, and run tests to verify. I'll start
  by reading the file.
 ╭────────────────────────────────────────────────────────╮
 │ ✔  ReadFile ...dia//ffmpeg_aac_bitstream_converter.cc  │
 ╰────────────────────────────────────────────────────────╯
✦ Got the file. Removing #pragma allow_unsafe_buffers and UNSAFE_TODO.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc: #ifdef UNSAFE_BUFFER… │
 │                                                                          │
 │     4                                                                    │
 │     5   #include "base/containers/span.h"                                │
 │     6                                                                    │
 │     7 - #ifdef UNSAFE_BUFFERS_BUILD                                      │
 │     8 - // TODO(crbug.com/40285824):                                     │
 │       Remove this and convert code to                                    │
 │       safer constructs.                                                  │
 │     9 - #pragma allow_unsafe_buffers                                     │
 │    10 - #endif                                                           │
 │     7                                                                    │
 │     8 +                                                                  │
 │     9   #include                                                         │
 │         "media/filters/ffmpeg_aac_bitstrea                               │
 │         m_converter.h"                                                   │
 │    10                                                                    │
 │    11   #include "base/logging.h"                                        │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Pragma's gone. Compiling media_filters to find unsafe buffer errors.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │                                                                          │
 │                                                                          │
 │     9.49s Schedule Failure: unknown target                               │
 │    "media_filters"                                                       │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ media_filters failed. I'll try building the media target instead.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:235:32: error: member                                  │
 │    reference base type 'uint8_t[7]' (aka                                 │
 │    'unsigned char[7]') is not a structure                                │
 │    or union                                                              │
 │      235 |   memcpy(dest_packet.data,                                    │
 │    hdr_.data(), kAdtsHeaderSize);                                        │
 │          |                                                               │
 │    ~~~~^~~~~                                                             │
 │    1 error generated.                                                    │
 │                                                                          │
 │                                                                          │
 │    17.64s Build Failure: 68 done 1 failed                                │
 │    4 remaining - 3.85/s                                                  │
 │     cannot make progress due to previous 1                               │
 │    errors: remote-exec                                                   │
 │    049198743aa6bc551105fe02a90ab3bb332c048                               │
 │    1a3287ac0e5cbfa6f5890daba/355 failed:                                 │
 │    exit=1                                                                │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Compiler error at ffmpeg_aac_bitstream_converter.cc:235:32: hdr_ isn't a
   span. I'll check its type in the header and fix the code.
 ╭────────────────────────────────────────────────────────╮
 │ ✔  ReadFile ...edia//ffmpeg_aac_bitstream_converter.h  │
 ╰────────────────────────────────────────────────────────╯
✦ hdr_ is a C-style array. The error's in ConvertPacket's memcpy, which
  should use hdr_ directly. In GenerateAdtsHeader, I'll replace memset with
  std::ranges::fill. In ConvertPacket, I'll create a span from
  dest_packet.data and use copy_from for the header, then create a span for
  packet->data to replace the second memcpy. I'll start with
  GenerateAdtsHeader.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   memset(reinterpret… │
 │                                                                          │
 │    34                         base::span<                                │
 │         uint8_t>hdr) {                                                   │
 │    35   DCHECK_EQ(codec, AV_CODEC_ID_AAC);                               │
 │    36                                                                    │
 │    37 - memset(reinterpret_cast<void                                     │
 │       *>(hdr.data()), 0,                                                 │
 │    38 -                                                                  │
 │       FFmpegAACBitstreamConverter::kAdtsHe                               │
 │       aderSize);                                                         │
 │    37 + std::ranges::fill(hdr, 0);                                       │
 │    38   // Ref:                                                          │
 │         http://wiki.multimedia.cx/index.ph                               │
 │         p?title=ADTS                                                     │
 │    39   // ADTS header structure is the                                  │
 │         following                                                        │
 │    40   // AAAAAAAA  AAAABCCD  EEFFFFGH                                  │
 │         HHIJKLMM  MMMMMMMM  MMMOOOOO                                     │
 │         OOOOOOPP                                                         │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Okay, ConvertPacket next. I'm replacing the memcpy calls by creating a
  dest_span and copying hdr_ and packet->data into it.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   memcpy(dest_packet… │
 │                                                                          │
 │    231   if (av_new_packet(&dest_packet,                                 │
 │          header_plus_packet_size) != 0)                                  │
 │    232     return false;  // Memory                                      │
 │          allocation failure.                                             │
 │    233                                                                   │
 │    234 - memcpy(dest_packet.data, hdr_.                                  │
 │        data(), kAdtsHeaderSize);                                         │
 │    235 - memcpy(reinterpret_cast<void                                    │
 │        *>(dest_packet.data +                                             │
 │        kAdtsHeaderSize),                                                 │
 │    236 -        reinterpret_cast<void                                    │
 │        *>(packet->data), packet->size);                                  │
 │    234 + auto dest_span =                                                │
 │        base::span(dest_packet.data,                                      │
 │        dest_packet.size);                                                │
 │    235 + dest_span.first(kAdtsHeaderSize)                                │
 │        .copy_from(base::span(hdr_));                                     │
 │    236 + dest_span.subspan                                               │
 │        (kAdtsHeaderSize)                                                 │
 │    237 +     .copy_from(base::span(packet                                │
 │        ->data, packet->size));                                           │
 │    238                                                                   │
 │    239   // This is a bit tricky: since                                  │
 │          the interface does not allow us                                 │
 │          to replace                                                      │
 │    240   // the pointer of the old packet                                │
 │          with a new one, we will initially                               │
 │          copy the                                                        │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Replaced memset and memcpy; now adding <algorithm>.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc: #include "base/conta… │
 │                                                                          │
 │     4                                                                    │
 │     5   #include "base/containers/span.h"                                │
 │     6                                                                    │
 │     7 + #include <algorithm>                                             │
 │     8                                                                    │
 │     9                                                                    │
 │    10 +                                                                  │
 │    11   #include                                                         │
 │         "media/filters/ffmpeg_aac_bitstrea                               │
 │         m_converter.h"                                                   │
 │    12                                                                    │
 │    13   #include "base/logging.h"                                        │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Compiling again to check changes.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │    In file included from                                                 │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:5:                                                     │
 │    In file included from                                                 │
 │    ../../base/containers/span.h:33:                                      │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    271:47: error: no matching function for                               │
 │    call to 'strict_cast'                                                 │
 │      271 |   constexpr StrictNumeric(Src                                 │
 │    value) : value_(strict_cast<T>(value))                                │
 │    {}                                                                    │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~                                                        │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:236:49: note: in                                       │
 │    instantiation of function template                                    │
 │    specialization                                                        │
 │    'base::internal::StrictNumeric<unsigned                               │
 │    long>::StrictNumeric<int>' requested                                  │
 │    here                                                                  │
 │      236 |   auto dest_span =                                            │
 │    base::span(dest_packet.data,                                          │
 │    dest_packet.size);                                                    │
 │          |                                                               │
 │    ^                                                                     │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    229:15: note: candidate template                                      │
 │    ignored: constraints not satisfied                                    │
 │    [with Dst = unsigned long, Src = int,                                 │
 │    SrcType = UnderlyingType<int>]                                        │
 │      229 | constexpr Dst strict_cast(Src                                 │
 │    value) {                                                              │
 │          |               ^                                               │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    227:7: note: because                                                  │
 │    'kStaticDstRangeRelationToSrcRange<unsi                               │
 │    gned long, int> ==                                                    │
 │    NumericRangeRepresentation::kContained'                               │
 │    evaluated to false                                                    │
 │      227 |                                                               │
 │    kStaticDstRangeRelationToSrcRange<Dst,                                │
 │    SrcType> ==                                                           │
 │          |       ^                                                       │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.h:24:3: note: unnamed type                                │
 │    used in template argument was declared                                │
 │    here                                                                  │
 │       24 |   enum { kAdtsHeaderSize = 7 };                               │
 │          |   ^                                                           │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.h:24:3: note: unnamed type                                │
 │    used in template argument was declared                                │
 │    here                                                                  │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.h:24:3: note: unnamed type                                │
 │    used in template argument was declared                                │
 │    here                                                                  │
 │    1 error generated.                                                    │
 │                                                                          │
 │                                                                          │
 │    17.47s Build Failure: 1 done 1 failed 4                               │
 │    remaining - 0.06/s                                                    │
 │     cannot make progress due to previous 1                               │
 │    errors: remote-exec                                                   │
 │    e52113d25489b036df731e9ed5638936a61067e                               │
 │    f5f97195f8f5767183aab1f86/355 failed:                                 │
 │    exit=1                                                                │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ base::span's constructor is choking on dest_packet.size because it's an
  int, not a size_t. I'll cast it to size_t and also fix the hdr_.data() I
  missed.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   auto dest_span = b… │
 │                                                                          │
 │    233   if (av_new_packet(&dest_packet,                                 │
 │          header_plus_packet_size) != 0)                                  │
 │    234     return false;  // Memory                                      │
 │          allocation failure.                                             │
 │    235                                                                   │
 │    236 - auto dest_span =                                                │
 │        base::span(dest_packet.data,                                      │
 │        dest_packet.size);                                                │
 │    236 + auto dest_span =                                                │
 │    237 +     base::span(dest_packet.data,                                │
 │        static_cast<size_t                                                │
 │        >(dest_packet.size));                                             │
 │    238   dest_span.first(kAdtsHeaderSize)                                │
 │          .copy_from(base::span(hdr_));                                   │
 │    239   dest_span.subspan                                               │
 │          (kAdtsHeaderSize)                                               │
 │    239 -     .copy_from(base::span(packet                                │
 │        ->data, packet->size));                                           │
 │    240 +     .copy_from(                                                 │
 │    241 +         base::span(packet->data,                                │
 │        static_cast<size_t                                                │
 │        >(packet->size)));                                                │
 │    242                                                                   │
 │    243   // This is a bit tricky: since                                  │
 │          the interface does not allow us                                 │
 │          to replace                                                      │
 │    244   // the pointer of the old packet                                │
 │          with a new one, we will initially                               │
 │          copy the                                                        │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Forgot to change hdr_.data() to hdr_ in ConvertPacket. Fixing it now.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:                     … │
 │                                                                          │
 │    216                                                                   │
 │          header_plus_packet_size,                                        │
 │    217                          0x7FF,  //                               │
 │          buffer fullness                                                 │
 │    218                          0,      //                               │
 │          one frame per packet                                            │
 │    219 -                        hdr_);                                   │
 │    219 +                        base::span                               │
 │        (hdr_));                                                          │
 │    220   codec_ =                                                        │
 │          stream_codec_parameters_->codec_i                               │
 │          d;                                                              │
 │    221   audio_profile_ =                                                │
 │          stream_codec_parameters_->profile                               │
 │          ;                                                               │
 │    222   sample_rate_index_ =                                            │
 │          sample_rate_index;                                              │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ I messed up. hdr_ is a member, GenerateAdtsHeader a free function. I
  can't pass hdr_ directly. Correcting the call to use base::span(hdr_).
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ x  Edit {"new_string":"                           0,      // one frame … │
 │                                                                          │
 │    Failed to edit, 0 occurrences found for                               │
 │    old_string in                                                         │
 │    /usr/local/google/home/keishi/gemini-ru                               │
 │    n/workdirs/chromium1/src/media/filters/                               │
 │    ffmpeg_aac_bitstream_converter.cc. No                                 │
 │    edits made. The exact text in                                         │
 │    old_string was not found. Ensure you're                               │
 │    not escaping content incorrectly and                                  │
 │    check whitespace, indentation, and                                    │
 │    context. Use read_file tool to verify.                                │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ replace failed; old_string not found. I'm confused. Rereading the file
  to verify its content.
 ╭────────────────────────────────────────────────────────╮
 │ ✔  ReadFile ...dia//ffmpeg_aac_bitstream_converter.cc  │
 ╰────────────────────────────────────────────────────────╯
✦ I was fixing a memcpy that I'd already replaced, trying to change hdr_
  to base::span(hdr_) when it was already correct. Recompiling now.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:195:9: error: unsafe                                   │
 │    buffer access                                                         │
 │    [-Werror,-Wunsafe-buffer-usage]                                       │
 │      195 |                                                               │
 │    ((stream_codec_parameters_->extradata[1                               │
 │    ] & 0x80) >> 7);                                                      │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                   │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:195:9: note: See                                       │
 │    //docs/unsafe_buffers.md for help.                                    │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:237:7: error: function                                 │
 │    introduces unsafe buffer manipulation                                 │
 │    [-Werror,-Wunsafe-buffer-usage]                                       │
 │      237 |                                                               │
 │    base::span(dest_packet.data,                                          │
 │    static_cast<size_t>(dest_packet.size));                               │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                               │
 │    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                          │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:237:7: note: See                                       │
 │    //docs/unsafe_buffers.md for help.                                    │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:241:11: error: function                                │
 │    introduces unsafe buffer manipulation                                 │
 │    [-Werror,-Wunsafe-buffer-usage]                                       │
 │      241 |                                                               │
 │    base::span(packet->data,                                              │
 │    static_cast<size_t>(packet->size)));                                  │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                               │
 │    ~~~~~~~~~~~~~~~~~~~~                                                  │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:241:11: note: See                                      │
 │    //docs/unsafe_buffers.md for help.                                    │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:252:3: error: function                                 │
 │    'memcpy' is unsafe                                                    │
 │    [-Werror,-Wunsafe-buffer-usage-in-libc-                               │
 │    call]                                                                 │
 │      252 |   memcpy(packet, &dest_packet,                                │
 │    sizeof(*packet));                                                     │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                               │
 │    ~~~~~~                                                                │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:252:3: note: See                                       │
 │    //docs/unsafe_buffers.md for help.                                    │
 │    4 errors generated.                                                   │
 │                                                                          │
 │                                                                          │
 │    18.61s Build Failure: 1 done 1 failed 4                               │
 │    remaining - 0.05/s                                                    │
 │     cannot make progress due to previous 1                               │
 │    errors: remote-exec                                                   │
 │    a07dab99ea43746107e37b1fdf8b550ae8915e3                               │
 │    528f4feeb6597cbd8aa69259e/355 failed:                                 │
 │    exit=1                                                                │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ I have four errors to fix. First, I'll wrap
  stream_codec_parameters_->extradata in a base::span to resolve the unsafe
  buffer access. Second and third, I'll use UNSAFE_BUFFERS to safely create
  spans from dest_packet.data and packet->data. Finally, I'll replace the
  unsafe memcpy with a direct assignment and move the av_packet_unref call
  to after the copy to avoid a dangling pointer. I'll begin with the
  extradata fix.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   if (stream_codec_p… │
 │                                                                          │
 │    190     DLOG(ERROR) << "extradata too                                 │
 │          small to contain MP4A header";                                  │
 │    191     return false;                                                 │
 │    192   }                                                               │
 │    193 + auto extradata =                                                │
 │        base::span(stream_codec_parameters_                               │
 │        ->extradata,                                                      │
 │    194 +                                                                 │
 │        stream_codec_parameters_->extradata                               │
 │        _size);                                                           │
 │    195   int sample_rate_index =                                         │
 │    194 -                                                                 │
 │        ((stream_codec_parameters_->extrada                               │
 │        ta[0] & 0x07) << 1) |                                             │
 │    195 -                                                                 │
 │        ((stream_codec_parameters_->extrada                               │
 │        ta[1] & 0x80) >> 7);                                              │
 │    196 +     ((extradata[0] & 0x07) << 1)                                │
 │        | ((extradata[1] & 0x80) >> 7);                                   │
 │    197   if (sample_rate_index > 12) {                                   │
 │    198     sample_rate_index = 4;                                        │
 │    199   }                                                               │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Okay, base::span constructors. Wrapping them in UNSAFE_BUFFERS.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   auto dest_span =..… │
 │                                                                          │
 │    234   if (av_new_packet(&dest_packet,                                 │
 │          header_plus_packet_size) != 0)                                  │
 │    235     return false;  // Memory                                      │
 │          allocation failure.                                             │
 │    236                                                                   │
 │    237 - auto dest_span =                                                │
 │    238 -     base::span(dest_packet.data,                                │
 │        static_cast<size_t                                                │
 │        >(dest_packet.size));                                             │
 │    237 + auto dest_span = UNSAFE_BUFFERS(                                │
 │    238 +     base::span(dest_packet.data,                                │
 │        static_cast<size_t                                                │
 │        >(dest_packet.size)));                                            │
 │    239   dest_span.first(kAdtsHeaderSize)                                │
 │          .copy_from(base::span(hdr_));                                   │
 │    240   dest_span.subspan                                               │
 │          (kAdtsHeaderSize)                                               │
 │    241 -     .copy_from(                                                 │
 │    242 -         base::span(packet->data,                                │
 │        static_cast<size_t                                                │
 │        >(packet->size)));                                                │
 │    241 +     .copy_from(UNSAFE_BUFFERS(                                  │
 │    242 +         base::span(packet->data,                                │
 │        static_cast<size_t                                                │
 │        >(packet->size))));                                               │
 │    243                                                                   │
 │    244   // This is a bit tricky: since                                  │
 │          the interface does not allow us                                 │
 │          to replace                                                      │
 │    245   // the pointer of the old packet                                │
 │          with a new one, we will initially                               │
 │          copy the                                                        │
 ╰──────────────────────────────────────────────────────────────────────────╯
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ x  Edit {"file_path":"/usr/local/google/home/keishi/gemini-run/workdirs… │
 │                                                                          │
 │    File path must be within one of the                                   │
 │    workspace directories:                                                │
 │    /usr/local/google/home/keishi/gemini-ru                               │
 │    n/workdirs/chromium1/src                                              │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Okay, memcpy and av_packet_unref next.
✦ Wrong file path. I'll use the correct one:
  /usr/local/google/home/keishi/gemini-run/workdirs/chromium1/src/media/filt
  ers/ffmpeg_aac_bitstream_converter.cc. I've also learned
  av_packet_move_ref is superior to memcpy for this task as it avoids data
  copying by moving the reference, so I'll use that instead.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   // metadata from o… │
 │                                                                          │
 │    246     // metadata from old packet to                                │
 │          new bigger packet.                                              │
 │    247     av_packet_copy_props                                          │
 │          (&dest_packet, packet);                                         │
 │    248                                                                   │
 │    249 -   // Release the old packet.                                    │
 │    249 +   // Release the old packet and                                 │
 │        move the new data into it.                                        │
 │    250     av_packet_unref(packet);                                      │
 │    251 -                                                                 │
 │    252 -   // Finally, replace the values                                │
 │        in the input packet.                                              │
 │    253 -   memcpy(packet, &dest_packet,                                  │
 │        sizeof(*packet));                                                 │
 │    251 +   *packet = dest_packet;                                        │
 │    252     return true;                                                  │
 │    253   }                                                               │
 │    254                                                                   │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Changes made. Recompiling.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │    In file included from                                                 │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:5:                                                     │
 │    In file included from                                                 │
 │    ../../base/containers/span.h:33:                                      │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    271:47: error: no matching function for                               │
 │    call to 'strict_cast'                                                 │
 │      271 |   constexpr StrictNumeric(Src                                 │
 │    value) : value_(strict_cast<T>(value))                                │
 │    {}                                                                    │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~                                                        │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:194:31: note: in                                       │
 │    instantiation of function template                                    │
 │    specialization                                                        │
 │    'base::internal::StrictNumeric<unsigned                               │
 │    long>::StrictNumeric<int>' requested                                  │
 │    here                                                                  │
 │      194 |                                                               │
 │    stream_codec_parameters_->extradata_siz                               │
 │    e);                                                                   │
 │          |                               ^                               │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    229:15: note: candidate template                                      │
 │    ignored: constraints not satisfied                                    │
 │    [with Dst = unsigned long, Src = int,                                 │
 │    SrcType = UnderlyingType<int>]                                        │
 │      229 | constexpr Dst strict_cast(Src                                 │
 │    value) {                                                              │
 │          |               ^                                               │
 │    ../../base/numerics/safe_conversions.h:                               │
 │    227:7: note: because                                                  │
 │    'kStaticDstRangeRelationToSrcRange<unsi                               │
 │    gned long, int> ==                                                    │
 │    NumericRangeRepresentation::kContained'                               │
 │    evaluated to false                                                    │
 │      227 |                                                               │
 │    kStaticDstRangeRelationToSrcRange<Dst,                                │
 │    SrcType> ==                                                           │
 │          |       ^                                                       │
 │    1 error generated.                                                    │
 │                                                                          │
 │                                                                          │
 │    15.81s Build Failure: 1 done 1 failed 4                               │
 │    remaining - 0.06/s                                                    │
 │     cannot make progress due to previous 1                               │
 │    errors: remote-exec                                                   │
 │    d1c89a2fe421586d1b46bd2a6fc9e905dfdeb00                               │
 │    23feed72df490a2ccb78d6cfa/355 failed:                                 │
 │    exit=1                                                                │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ strict_cast error again. extradata span creation is failing because
  extradata_size is an int. I need to cast it to size_t.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   auto extradata = b… │
 │                                                                          │
 │    190     DLOG(ERROR) << "extradata too                                 │
 │          small to contain MP4A header";                                  │
 │    191     return false;                                                 │
 │    192   }                                                               │
 │    193 - auto extradata =                                                │
 │        base::span(stream_codec_parameters_                               │
 │        ->extradata,                                                      │
 │    194 -                                                                 │
 │        stream_codec_parameters_->extradata                               │
 │        _size);                                                           │
 │    193 + auto extradata =                                                │
 │    194 +     base::span                                                  │
 │        (stream_codec_parameters_->                                       │
 │        extradata,                                                        │
 │    195 +                static_cast<size_t                               │
 │        >(stream_codec_parameters_->extrada                               │
 │        ta_size));                                                        │
 │    196   int sample_rate_index =                                         │
 │    197       ((extradata[0] & 0x07) << 1)                                │
 │          | ((extradata[1] & 0x80) >> 7);                                 │
 │    198   if (sample_rate_index > 12) {                                   │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Compiling.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 │                                                                          │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:194:7: error: function                                 │
 │    introduces unsafe buffer manipulation                                 │
 │    [-Werror,-Wunsafe-buffer-usage]                                       │
 │      194 |                                                               │
 │    base::span(stream_codec_parameters_->ex                               │
 │    tradata,                                                              │
 │          |                                                               │
 │    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                               │
 │    ~~~~~~~~                                                              │
 │      195 |                                                               │
 │    static_cast<size_t>(stream_codec_parame                               │
 │    ters_->extradata_size));                                              │
 │          |                                                               │
 │    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                               │
 │    ~~~~~~~~~~~~~~~~~~~~~~~                                               │
 │    ../../media/filters/ffmpeg_aac_bitstrea                               │
 │    m_converter.cc:194:7: note: See                                       │
 │    //docs/unsafe_buffers.md for help.                                    │
 │    1 error generated.                                                    │
 │                                                                          │
 │                                                                          │
 │    16.22s Build Failure: 1 done 1 failed 4                               │
 │    remaining - 0.06/s                                                    │
 │     cannot make progress due to previous 1                               │
 │    errors: remote-exec                                                   │
 │    2f2615b89bfe01b86a9475ea498df8d1b502010                               │
 │    34abebca08d939c09c45f8657/355 failed:                                 │
 │    exit=1                                                                │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Forgot UNSAFE_BUFFERS for extradata span.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Edit ...dia//ffmpeg_aac_bitstream_converter.cc:   auto extradata =..… │
 │                                                                          │
 │    190     DLOG(ERROR) << "extradata too                                 │
 │          small to contain MP4A header";                                  │
 │    191     return false;                                                 │
 │    192   }                                                               │
 │    193 - auto extradata =                                                │
 │    193 + auto extradata = UNSAFE_BUFFERS(                                │
 │    194       base::span                                                  │
 │          (stream_codec_parameters_->                                     │
 │          extradata,                                                      │
 │    195 -                static_cast<size_t                               │
 │        >(stream_codec_parameters_->extrada                               │
 │        ta_size));                                                        │
 │    195 +                static_cast<size_t                               │
 │        >(stream_codec_parameters_->extrada                               │
 │        ta_size)));                                                       │
 │    196   int sample_rate_index =                                         │
 │    197       ((extradata[0] & 0x07) << 1)                                │
 │          | ((extradata[1] & 0x80) >> 7);                                 │
 │    198   if (sample_rate_index > 12) {                                   │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Compiling.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell agents/extensions/landmines/agent_autoninja -C out/Default med… │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ Build's done. Running media_unittests.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell tools/autotest.py -C out/Default media_unittests (Run media_un… │
 │                                                                          │
 │                                                                          │
 │    Target "media_unittests" did not match                                │
 │    any files.                                                            │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ media_unittests isn't a valid test target. I'll list out/Default to find
   the right one.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell ls out/Default (List files in out/Default to find the correct … │
 │                                                                          │
 │    ... first 1222 lines hidden ...                                       │
 │    v8_simple_wasm_compile_simd_fuzzer                                    │
 │    v8_simple_wasm_compile_wasmgc_fuzzer                                  │
 │    v8_simple_wasm_deopt_fuzzer                                           │
 │    v8_simple_wasm_init_expr_fuzzer                                       │
 │    v8_simple_wasm_module_fuzzer                                          │
 │    v8_simple_wasm_streaming_fuzzer                                       │
 │    v8_unittests                                                          │
 │    vaapi_unittest                                                        │
 │    vaapi_unittest.runtime_deps                                           │
 │    variations_desktop_smoke_tests.runtime_                               │
 │    deps                                                                  │
 │    variations_smoke_tests.runtime_deps                                   │
 │    variations_unittests                                                  │
 │    variations_unittests.runtime_deps                                     │
 │    video_decode_accelerator_perf_tests                                   │
 │    video_decode_accelerator_perf_tests.run                               │
 │    time_deps                                                             │
 │    video_decode_accelerator_tests                                        │
 │    video_decode_accelerator_tests.runtime_                               │
 │    deps                                                                  │
 │    video_encode_accelerator_perf_tests                                   │
 │    video_encode_accelerator_perf_tests.run                               │
 │    time_deps                                                             │
 │    video_encode_accelerator_tests                                        │
 │    video_encode_accelerator_tests.runtime_                               │
 │    deps                                                                  │
 │    video_replay                                                          │
 │    views_examples                                                        │
 │    views_examples_resources.pak                                          │
 │    views_examples_unittests                                              │
 │    views_examples_unittests.runtime_deps                                 │
 │    views_examples_with_content                                           │
 │    views_perftests                                                       │
 │    views_perftests.runtime_deps                                          │
 │    views_unittests                                                       │
 │    views_unittests.runtime_deps                                          │
 │    viz_demo                                                              │
 │    viz_perftests                                                         │
 │    viz_perftests.runtime_deps                                            │
 │    viz_unittests                                                         │
 │    viz_unittests.runtime_deps                                            │
 │    vk_swiftshader_icd.json                                               │
 │    vp8_encoder_fuzz_test                                                 │
 │    vp8_encoder_fuzz_test.runtime_deps                                    │
 │    vp9_encoder_fuzz_test                                                 │
 │    vp9_encoder_fuzz_test.runtime_deps                                    │
 │    vr_common_perftests                                                   │
 │    vr_common_perftests.runtime_deps                                      │
 │    vr_common_unittests                                                   │
 │    vr_common_unittests.runtime_deps                                      │
 │    vr_test.pak                                                           │
 │    vr_test.pak.info                                                      │
 │    vulkan_tests                                                          │
 │    vulkan_tests.runtime_deps                                             │
 │    wami                                                                  │
 │    wasm_api_tests                                                        │
 │    watermark_app                                                         │
 │    wayland_scanner                                                       │
 │    web_application_fuzztests                                             │
 │    web_application_fuzztests.runtime_deps                                │
 │    webcrypto_testing_fuzzer                                              │
 │    webcrypto_testing_fuzzer.runtime_deps                                 │
 │    webgpu_blink_web_tests.runtime_deps                                   │
 │    webui_examples                                                        │
 │    webui_examples.pak                                                    │
 │    webui_examples.pak.info                                               │
 │    webui_resources_tools_python_unittests.                               │
 │    runtime_deps                                                          │
 │    wm_unittests                                                          │
 │    wm_unittests.runtime_deps                                             │
 │    wtf_unittests                                                         │
 │    wtf_unittests.runtime_deps                                            │
 │    xdg-mime                                                              │
 │    xdg-settings                                                          │
 │    xr_browser_tests_binary                                               │
 │    xr_browser_tests_binary.runtime_deps                                  │
 │    xr_browser_tests.runtime_deps                                         │
 │    xvfb_py_unittests.runtime_deps                                        │
 │    zlib_bench                                                            │
 │    zlib_unittests                                                        │
 │    zlib_unittests.runtime_deps                                           │
 │    zpipe                                                                 │
 │    zucchini                                                              │
 │    zucchini_integration_test                                             │
 │    zucchini_integration_test.runtime_deps                                │
 │    zucchini_unittests                                                    │
 │    zucchini_unittests.runtime_deps                                       │
 │    zxcvbn_unittests                                                      │
 │    zxcvbn_unittests.runtime_deps                                         │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ media_unittests is on the list. Retrying.
 ╭──────────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell tools/autotest.py -C out/Default media_unittests (Run media_un… │
 │                                                                          │
 │                                                                          │
 │    Target "media_unittests" did not match                                │
 │    any files.                                                            │
 │                                                                          │
 ╰──────────────────────────────────────────────────────────────────────────╯
✦ autotest.py isn't working with media_unittests, so I'll run the binary
  directly.
 ╭───────────────────────────────────────────────────────────────────────╮
 │ ✔  Shell out/Default/media_unittests (Run media_unittests directly.)  │
 │                                                                       │
 │    ... first 26537 lines hidden ...                                   │
 │    B__ (140 ms)                                                       │
 │    [8250/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile0__PIXEL_FORMAT_I420__ (422 ms)                              │
 │    [8251/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile0__PIXEL_FORMAT_NV12__ (411 ms)                              │
 │    [8252/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile0__PIXEL_FORMAT_XRGB__ (395 ms)                              │
 │    [8253/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile1__PIXEL_FORMAT_I444__ (515 ms)                              │
 │    [8254/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile1__PIXEL_FORMAT_NV12__ (573 ms)                              │
 │    [8255/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile1__PIXEL_FORMAT_XRGB__ (570 ms)                              │
 │    [8256/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile2__PIXEL_FORMAT_I420__ (508 ms)                              │
 │    [8257/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile2__PIXEL_FORMAT_NV12__ (480 ms)                              │
 │    [8258/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile2__PIXEL_FORMAT_XRGB__ (471 ms)                              │
 │    [8259/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile3__PIXEL_FORMAT_I444__ (646 ms)                              │
 │    [8260/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile3__PIXEL_FORMAT_NV12__ (648 ms)                              │
 │    [8261/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp9__vp9_p                            │
 │    rofile3__PIXEL_FORMAT_XRGB__ (645 ms)                              │
 │    [8262/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp8__vp8__                            │
 │    PIXEL_FORMAT_I420__ (140 ms)                                       │
 │    [8263/8273]                                                        │
 │    VpxGeneric/SoftwareVideoEncoderTest.Enc                            │
 │    odeAndDecodeWithEnablingDrop/vp8__vp8__                            │
 │    PIXEL_FORMAT_XRGB__ (136 ms)                                       │
 │    [8264/8273]                                                        │
 │    PipelineIntegrationTest.BasicPlaybackHa                            │
 │    shed (91 ms)                                                       │
 │    [8265/8273]                                                        │
 │    PipelineIntegrationTest.WaveLayoutChang                            │
 │    e (9 ms)                                                           │
 │    [8266/8273]                                                        │
 │    PipelineIntegrationTest.PlaybackStereo4                            │
 │    8000hz (12 ms)                                                     │
 │    [8267/8273]                                                        │
 │    PipelineIntegrationTest.PlaybackWithAud                            │
 │    ioTrackDisabledThenEnabled (2915 ms)                               │
 │    [8268/8273]                                                        │
 │    PipelineIntegrationTest.PlaybackWithVid                            │
 │    eoTrackDisabledThenEnabled (2947 ms)                               │
 │    [8269/8273]                                                        │
 │    PipelineIntegrationTest.TrackStatusChan                            │
 │    gesBeforePipelineStarted (2 ms)                                    │
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 │    gesAfterPipelineEnded (78 ms)                                      │
 │    [8271/8273]                                                        │
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 │    gesWhileSuspended (2890 ms)                                        │
 │    [8272/8273]                                                        │
 │    PipelineIntegrationTest.ReinitRenderers                            │
 │    WhileAudioTrackIsDisabled (185 ms)                                 │
 │    [8273/8273]                                                        │
 │    PipelineIntegrationTest.ReinitRenderers                            │
 │    WhileVideoTrackIsDisabled (172 ms)                                 │
 │    SUCCESS: all tests passed.                                         │
 │    Tests took 47 seconds.                                             │
 │                                                                       │
 ╰───────────────────────────────────────────────────────────────────────╯
✦ Tests passed, changes correct. Task complete.
 ╭──────────────────────────────────────────────────────────────────────╮
 │ ⊶  Shell echo "GEMINI_JOB_COMPLETE_GEMINI" (Signal that the job is … │
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⠙ Completed the task.
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