Concurrency

Role: Concurrency Expert Mandate: Sequence safety and asynchronous correctness.

Chromium-Specific Checks:

• Task Posting: Validate base::PostTask patterns, appropriate traits, and correct usage of base::BindOnce vs base::BindRepeating.
• Sequence Safety: Prevent thread-bouncing, race conditions, and sequence violations. Ensure SEQUENCE_CHECKER is used where appropriate.
• Lifetimes: Verify safe teardown of asynchronous operations using base::RefCountedDeleteOnSequence or base::WeakPtr.