Fix the potential vulnerability in CheckMembership function

The std:equal used to compare two blobs of data had a risk
of out-of-bounds. The fix is adding the condition about the size.

Bug: b:524176462
Change-Id: Ib72ec0e43e32a5ac5664560928a0925234d30d59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8010516
Commit-Queue: Amr Aboelkher <amraboelkher@chromium.org>
Commit-Queue: Igor <igorcov@chromium.org>
Reviewed-by: Amr Aboelkher <amraboelkher@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1654039}
NOKEYCHECK=True
GitOrigin-RevId: a22ff9d11f228bd1c2e377f55d103671bb6e9e59