Prefer the canvas2d MSAA sample count setting over canvas2d AA setting.
Prefer the canvas2d MSAA sample count setting over canvas2d AA setting.

BUG=314214

Review URL: https://codereview.chromium.org/56513004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@161280 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs