tree b26d30e110f70891e1edf02e8509a1020ce4bb2c
parent c695e954174e4a789631ea4d6e171bd7118ebc67
author kkinnunen <kkinnunen@nvidia.com> 1421413476 -0800
committer Commit bot <commit-bot@chromium.org> 1421413476 -0800

Fold alpha to the draw in savelayer-draw-restore patterns with non-opaque draw

Fold alpha of a save layer call to the subsequent draw call paint, even when
the draw call paint color is already non-opaque.

Comparing the difference of the unoptimized and the optimized call pattern
with all (layer alpha, draw alpha) combinations, this produces
off-by-one pixels ~50% of the time.

Reduces layers of current desk_carsvg.skp (recorded with cross-process
picture image filters allowed) from 122 to 115.

BUG=skia:3119

Review URL: https://codereview.chromium.org/840483005