This reverts commit f3ebd312f2.
Reason for revert: unhappy bots
Original change's description:
> add getAlphaf() to pixmap/bitmap
>
> Convenient for just extracting alpha (and more efficient than getColor()) and
> works for super-normal formats w/o loss of precision.
>
> Somewhat inspired by examining multiple chrome call-sites for getColor(), where
> chrome only really cared about the alpha. This new method runs about twice
> as fast as getColor() for the simple cases (i.e. no colorspace xforms), and
> even faster in the complex cases (since retrieving alpha doesn't care about
> colorspaces).
>
> Bug: skia:
> Change-Id: I7cd5a2c7f78de781aaa69dd1aa0dba3c532fcb73
> Reviewed-on: https://skia-review.googlesource.com/155606
> Commit-Queue: Mike Reed <reed@google.com>
> Reviewed-by: Mike Klein <mtklein@google.com>
TBR=mtklein@google.com,reed@google.com
Change-Id: I82ce00c09d16bf3e9b04f1c1bccd8cc6aa706ab2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/156000
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
be852e44ef