The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/08a150acae681dfa3abe9908919cdeea3b2416ce

commit 08a150acae681dfa3abe9908919cdeea3b2416ce
Author: Justin Novosad <junov@chromium.org>
Date: Mon Aug 21 23:39:08 2017

Fix OffscreenCanvas resizing behavior

This change ensures that the width and height attributes of
a placeholder canvas reflect the size of frames committed
on the OffscreenCanvas. Also, an exception is thrown if
an attempt is made to set a size attribute on a placeholder
canvas.

BUG= 754733 ,  754736 

TBR=zmo@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I6ec4296df5f8d47e22753e40e91eee616a3f9399
Reviewed-on: https://chromium-review.googlesource.com/612513
Reviewed-by: Justin Novosad <junov@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Justin Novosad <junov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496120}
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/content/test/gpu/gpu_tests/pixel_expectations.py
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/content/test/gpu/gpu_tests/pixel_test_pages.py
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/content/test/gpu/gpu_tests/webgl2_conformance_expectations.py
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/third_party/WebKit/LayoutTests/external/wpt/offscreen-canvas/the-offscreen-canvas/offscreencanvas.resize.html
[delete] https://crrev.com/59da685e80c1554da5cf7e95e2c3442fc8978761/third_party/WebKit/LayoutTests/external/wpt/offscreen-canvas/the-offscreen-canvas/offscreencanvas.transfercontrol.to.offscreen-expected.txt
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/third_party/WebKit/LayoutTests/external/wpt/offscreen-canvas/the-offscreen-canvas/offscreencanvas.transfercontrol.to.offscreen.html
[delete] https://crrev.com/59da685e80c1554da5cf7e95e2c3442fc8978761/third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-resize.html
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp
[modify] https://crrev.com/08a150acae681dfa3abe9908919cdeea3b2416ce/third_party/WebKit/Source/platform/graphics/OffscreenCanvasPlaceholder.h