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This uses a PaintRecorder to get at the canvas() for painting, instead
of grabbing it directly off PaintContext. This will allow PaintContext
to be backed by a DisplayItemList instead of a Canvas.

R=sadrul, sky
BUG=466426

Review URL: https://codereview.chromium.org/1064763002

Cr-Commit-Position: refs/heads/master@{#324080}