Remove use of GrColorType on GrCaps::getRenderTargetSampleCount.

Additionally this changes removes the version of the call that that takes
a GrPixelConfig.

As part of this change many call sites that were calling getRTSampleCount
to just check renderability have been changed to call
isFormat[AsColorType]Renderable instead. This change has also started to
move us to just checking format renderability (without GrCT) in classes
that are specifically dealing with GrSurface (GrResourceProvider, GrGpu, etc.).

Bug: skia:6718
Change-Id: Icf4a1a21a81a44e6863a7cd2059d21b9833d581f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/233039
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
26 files changed