This is change is currently still safe since earlier in Skia we are still requiring
the dst to be opaque. The change is a workaround to spots where trying to read the
dst to do in shader blending is failing for some reason. This also should give back
a little performance since doing dual source blending should be better than shader
blends.
Bug: chromium:732341
Change-Id: I795f8a520f87f3fbf5d63a9509fbd9f394ea2b29
Reviewed-on: https://skia-review.googlesource.com/19703
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
b54bdef86e