As part of the ClientSharedImage refactorization, this CL replaces
the mailbox member in PPB_Graphics3D_Impl::ColorBuffer with
ClientSharedImage, and adds other necessary code changes to support
this replacement.
Bug: 1494911, 1499992
Change-Id: Ie6800b427f70179dbf7cfabacdf49174377a551d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5056072
Reviewed-by: Vasiliy Telezhnikov <vasilyt@chromium.org>
Commit-Queue: Mingjing Zhang <mjzhang@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1228872}
9c3851af60