remove linear-blended sRGB dst support in software

This is the mechanism we'd want to add back if we add an sRGBA
SkColorType.  This will break the DM "srgb" config hard.

Landing this first should help flush out GMs that are incidentally using
sRGB offscreens.

Updated tests/AnimatedImageTest.cpp to avoid linear sRGB 8888 surfaces.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Change-Id: Idb5035cf4d60fcd1dc24c303d43a406fc4a603fa
Reviewed-on: https://skia-review.googlesource.com/132261
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed