The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/76d87e592a78e48415d636953de367da57c100bd

commit 76d87e592a78e48415d636953de367da57c100bd
Author: Justin Novosad <junov@chromium.org>
Date: Mon May 29 21:40:38 2017

Refactor OffscreenCanvas Resource tracking

This change refactors OffscreenCanvasFrameDispatcheImpl to make it
track resources locked for the compositor, using a single hash map
instead of one per resource type. This change also allows resources
to by recycled in order to reduce resource allocation ovehead.
In particular, mailbox generation and texture allocation are costly.
This CL does solve mailbox recycling for the GPU-accelerated use case.

Bug:  725926 
Change-Id: I34c3261de63c274c07c99b29529154508f697d32
Reviewed-on: https://chromium-review.googlesource.com/513613
Commit-Queue: Justin Novosad <junov@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#475384}
[modify] https://crrev.com/76d87e592a78e48415d636953de367da57c100bd/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
[modify] https://crrev.com/76d87e592a78e48415d636953de367da57c100bd/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h