This is mostly dead code.
In order to make it truly dead, we need to opt drawing unpremul images
into SkRasterPipelineBlitter. They had been handled by
SkLinearBitmapPipeline, but can't be draw by SkBitmapProcLegacyShader.
Drawing unpremul images is tested by the GM all_variants_8888, which
gave us trouble last time around (serialize-8888 drew right, 8888 wrong)
but now draws fine. I think this was probably also the root of the
revert, drawing some unpremul image in Chrome's tests somewhere.
Change-Id: I453f9df44ade807316935921cbae82961e2f08aa
Reviewed-on: https://skia-review.googlesource.com/24862
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
0fddb2d7c1