Remove GrTextureGradientColorizer and use GrTextureEffect instead.

Gradient colorizers are now sampled via explicit coordinates instead of
by passing coordinate data in a color channel. This change caused the
GrTextureGradientColorizer to become a no-op/passthrough effect.

Change-Id: I5233c93914716cac186b0ea8f5a3698746a89742
Bug: skia:10548
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/307298
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
7 files changed