As pointed out by jbauman@, doing this will result in creating un-necessary gpu process when we just need to query --disable-gpu-compositing flag, which could be quite inefficient.

So changing this to be "Plumb --disable-gpu-compositing to Blink"

Makes sense. For webgl it will have a context already so it wouldn't be relevant I guess. But for canvas if it was 2d it would not have a context, and just wants to know if it needs to upload to a texture or not. If not, no need for a context/gpu process.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c234ff9ce6b4ce3c1561dc99ef30837d4000101e

commit c234ff9ce6b4ce3c1561dc99ef30837d4000101e
Author: xidachen <xidachen@chromium.org>
Date: Tue Oct 04 02:10:50 2016

Expose --disable-gpu-compositing browser arg to Blink

Currently in Blink, there is no indication whether a compositor is GPU
accelerated or software. This CL plumbs it to Blink, so that we can
query whether --disable-gpu-compositing or --disable-gpu is set or not.

BUG= 650795 

Review-Url: https://codereview.chromium.org/2377883002
Cr-Commit-Position: refs/heads/master@{#422672}

[modify] https://crrev.com/c234ff9ce6b4ce3c1561dc99ef30837d4000101e/content/child/runtime_features.cc
[modify] https://crrev.com/c234ff9ce6b4ce3c1561dc99ef30837d4000101e/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
[modify] https://crrev.com/c234ff9ce6b4ce3c1561dc99ef30837d4000101e/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
[modify] https://crrev.com/c234ff9ce6b4ce3c1561dc99ef30837d4000101e/third_party/WebKit/public/web/WebRuntimeFeatures.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/570d8768c9645b4c9936461087174241df70fdeb

commit 570d8768c9645b4c9936461087174241df70fdeb
Author: xidachen <xidachen@chromium.org>
Date: Thu Oct 06 00:24:28 2016

Stop exposing --disable-gpu-compositing as a Blink RuntimeEnabledFeature

My previous CL makes this flag as a RuntimeEnabledFeature under Blink
which can be query anywhere in Blink. This CL move it to
public/platform/Platform.h. We put an extra note in there saying that
this function should never be called from core/ and modules/, should only
be called from platform/graphics.

BUG= 650795 

Review-Url: https://codereview.chromium.org/2391753003
Cr-Commit-Position: refs/heads/master@{#423353}

[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/child/runtime_features.cc
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/renderer/renderer_blink_platform_impl.cc
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/renderer/renderer_blink_platform_impl.h
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/public/platform/Platform.h
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/public/web/WebRuntimeFeatures.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/570d8768c9645b4c9936461087174241df70fdeb

commit 570d8768c9645b4c9936461087174241df70fdeb
Author: xidachen <xidachen@chromium.org>
Date: Thu Oct 06 00:24:28 2016

Stop exposing --disable-gpu-compositing as a Blink RuntimeEnabledFeature

My previous CL makes this flag as a RuntimeEnabledFeature under Blink
which can be query anywhere in Blink. This CL move it to
public/platform/Platform.h. We put an extra note in there saying that
this function should never be called from core/ and modules/, should only
be called from platform/graphics.

BUG= 650795 

Review-Url: https://codereview.chromium.org/2391753003
Cr-Commit-Position: refs/heads/master@{#423353}

[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/child/runtime_features.cc
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/renderer/renderer_blink_platform_impl.cc
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/content/renderer/renderer_blink_platform_impl.h
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/public/platform/Platform.h
[modify] https://crrev.com/570d8768c9645b4c9936461087174241df70fdeb/third_party/WebKit/public/web/WebRuntimeFeatures.h

[Automated comment] removing mislabelled merge-merged-2840