tree 1b99cd8fb5d2c0660ef2794afe836c622188ba1a
parent 5b1a2ca8c5c7b33aee7c1260d1161ba6c8cd6820
author mtklein <mtklein@chromium.org> 1458696644 -0700
committer Commit bot <commit-bot@chromium.org> 1458696645 -0700

Use Sk4x4f in srcover_srgb_dst_1.

I've also pulled out the common parts shared with sRGB srcover_n,
and rearranged to make the similarities a bit more clear.

This speeds up about 25%.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1829513002

Review URL: https://codereview.chromium.org/1829513002