remove old shader routines from SkColor4Shader

They don't handle drawing to untagged destinations
correctly, drawing as if sRGB rather than as if src.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I1d312c6fcd582e0ccd3f3aaf07526e18f67f7169
Reviewed-on: https://skia-review.googlesource.com/c/166480
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed