Ignore srcAlpha when the input is CMYK

Passing the (obvious) Opaque would cause us to set K=1, leading to an
all black image. Passing Premul would do even stranger things.

Change-Id: Iaf95fce581d32d58e34811547c6d31ec64856753
Reviewed-on: https://skia-review.googlesource.com/128315
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
1 file changed