Add support for runtime flags for experimental blending to chromium BUG=154769, 229220
Add support for runtime flags for experimental blending to chromium
BUG=154769, 229220

Review URL: https://codereview.chromium.org/13538003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148489 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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