Define SK_PICTURE_CLONE_NOOP.
This makes SkPicture::clone() a cheap ref, meaning impl-side painting will render
tiles concurrently from the same source SkPicture rather than from clones.
After testing for a few months in Skia, we believe SkPicture is thread safe enough
to try this out on the Chrome bots. Please revert this at the slightest sign of
crash, flaky drawing, etc.
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_layout_rel
BUG=
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288096
Review URL: https://codereview.chromium.org/
445373003
Cr-Commit-Position: refs/heads/master@{#288233}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288233 0039d316-1c4b-4281-b951-d872f2087c98