Use SkImage::newImageSnapshot() in CanvasIMageSource::getImageSourceForCanvas().

When repeatedly creating a pattern from a canvas or when doing a canvas-to-canvas copy,  additional memory is allocated even if the canvas' content don't change between the calls to createPattern() (cf benchmark in the bug 344804, message #7).

The idea is to use a SkImage obtained by calling newImageSnapshot() on the SkSurface encapsulated by the HTMLCanvasElement. This way a new bitmap is created only if the canvas is changed.

This CL depends on the CLs:
- https://codereview.chromium.org/416543002/ (merged)
- https://codereview.chromium.org/406673003/ for SkImage::isOpaque() (merged)


BUG=344804,170021,257428

Review URL: https://codereview.chromium.org/358893002

git-svn-id: svn://svn.chromium.org/blink/trunk@182967 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/613343002

git-svn-id: svn://svn.chromium.org/blink/trunk@182968 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: use MainFrameNavigated, not DocumentUpdated to re-enable Tracing agent to avoid races with DOMModel loading document.

BUG=

Review URL: https://codereview.chromium.org/618803002

git-svn-id: svn://svn.chromium.org/blink/trunk@182969 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/620553005

git-svn-id: svn://svn.chromium.org/blink/trunk@182970 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove default args to several PageWidgetDelegate members, try 3

BUG=411993

Review URL: https://codereview.chromium.org/620593002

git-svn-id: svn://svn.chromium.org/blink/trunk@182971 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add pseudoElement info to node tree dump.

Currently pseudoElements aren't displayed when dumping the dom tree. This
can make it difficult to know if they've been created or not. This CL
dumps out some information for each node that has pseudoElements so you
will know if they've been created and who their parent node is.

Review URL: https://codereview.chromium.org/606183002

git-svn-id: svn://svn.chromium.org/blink/trunk@182972 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/618913002

git-svn-id: svn://svn.chromium.org/blink/trunk@182973 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/617923003

git-svn-id: svn://svn.chromium.org/blink/trunk@182974 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Gardening stuff.

Mark http/tests/w3c/webperf/submission/Google/resource-timing/html/test_resource_initiator_types.html as fail on Mac.

BUG=418091
TEST=
TBR=wangxianzhu@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/621513002

git-svn-id: svn://svn.chromium.org/blink/trunk@182975 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/620613003

git-svn-id: svn://svn.chromium.org/blink/trunk@182976 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r182920

http://src.chromium.org/viewvc/blink?view=revision&revision=182920

BUG=334269
TBR=dominik.rottsches@intel.com

Review URL: https://codereview.chromium.org/618093002

git-svn-id: svn://svn.chromium.org/blink/trunk@182977 bbb929c8-8fbe-4397-9dbb-9b2b20218538