Remove #pragma allow_unsafe_buffers and add PA_UNSAFE_TODO annotations.

This change removes the #pragma allow_unsafe_buffers from several
allocator shim files. Instead of a blanket allowance, specific
potentially unsafe buffer operations are now wrapped with
PA_UNSAFE_TODO() to highlight areas needing future review for buffer
safety.

Previously a couple Apple/Window specific files were missed.

Change-Id: Idf2384cc537439e219c4e97832386d4f4d3d88d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7692652
Reviewed-by: Arthur Sonzogni <[email protected]>
Commit-Queue: Stephen Nusko <[email protected]>
Auto-Submit: Stephen Nusko <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1603341}
NOKEYCHECK=True
GitOrigin-RevId: a1d71cc9284e11d690debe65a3cf108941782598
7 files changed