Remove color argument from sampleShader.

Passing a color to a shader isn't supported in SkSL anymore.

Change-Id: Ic2743e519b69fa8add4c010166032b4dab2152a7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/431938
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
8 files changed