cc/paint: Remove PaintCanvas::peekPixels.

This patch removes peekPixels and replaces callers with an explicit
SkBitmap construction and PaintCanvas (as opposed to PaintSurface).

R=enne@chromium.org
TBR=jochen@chromium.org
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2758413002
Cr-Commit-Position: refs/heads/master@{#458880}
17 files changed