Handle gray alpha conversions in SkSwizzler
Nothing fancy here. By doing the entire conversion ourselves, we
only need to make one conversion pass over each row. Additionally,
we optimize the premultiply since we know each color component of
the pixel is identical.
This will also enable us to follow up with platform specific
optimizations.
PNG Decode Time Nexus 6P (for a test set of GrayAlpha encoded PNGs)
Regular Unpremul 0.95x
Zero Init Unpremul 0.94x
Regular Premul 0.91x
Zero Init Premul 0.90x
BUG=skia:4767
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1665583002
Review URL: https://codereview.chromium.org/1665583002
3 files changed