spanification: Add `#pragma allow_unsafe_buffers` to third_party/blink/

https://chromium.googlesource.com/chromium/src/+/main/docs/unsafe_buffers.md#suppressions

This is a preparation to fix each files.
This CL has no behavior changes.

Bug: 351564777
Change-Id: I6d041c3e8dad77f6050a54d10b56e7ff9f704a28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5689662
Auto-Submit: Kent Tamura <tkent@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1325421}
NOKEYCHECK=True
GitOrigin-RevId: 965bfa17fa39cdfac965d9dfd4a6ce736e490d4d
1 file changed