media: fix heap-use-after-free in CobaltAudioRendererSink

[kjyoun]

Refactor CobaltAudioRendererSink to manage SbAudioSink lifecycle
with std::unique_ptr and a custom deleter. This guarantees proper
destruction of the audio sink when the renderer sink is destroyed or
reset.

This change prevents background ALSA threads from accessing a freed
SbAudioSink object, addressing a heap-use-after-free ASAN error seen
when UpdateSourceStatus was called on a freed instance.

Issue: 483384414

[github-actions]

🤖 Gemini Suggested Commit Message

---

media: Fix heap-use-after-free in audio renderer sink

Refactor CobaltAudioRendererSink to manage SbAudioSink lifecycle
with std::unique_ptr and a custom deleter. This guarantees proper
destruction of the audio sink when the renderer sink is destroyed or
reset.

This change prevents background ALSA threads from accessing a freed
SbAudioSink object, addressing a heap-use-after-free ASAN error seen
when UpdateSourceStatus was called on a freed instance.

Bug: 483384414

---

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[kjyoun]

/gemini review

[gemini-code-assist]

Code Review

This pull request effectively resolves a heap-use-after-free vulnerability in CobaltAudioRendererSink by employing a std::unique_ptr with a custom deleter to manage the lifecycle of SbAudioSink. This change correctly applies the RAII principle to ensure the audio sink is always deallocated, even in error paths or during object destruction. The implementation is solid and directly addresses the issue. I have one suggestion to introduce a type alias for the unique_ptr, which would improve code readability and maintainability.

[gemini-code-assist]

Code Review

This pull request effectively addresses a heap-use-after-free bug by managing the SbAudioSink lifecycle with a std::unique_ptr and a custom deleter. This is a solid approach to ensure proper resource management. My review includes a few suggestions to align the implementation more closely with idiomatic C++ practices for handling C-style opaque pointers with smart pointers, which will improve code clarity and maintainability.