Rework GrRenderTargetOpList::setupDstReadIfNecessary.

Move the necessary check to the caller. This removes the GrPipelineBuilder
param which makes this useable with future GrDrawOps that can be recorded without one.

Rename to setupDstTexture(). This only is involved in the texture method of getting the
destination color to the XP.

Change-Id: I1b781da3d42586534470a23a572805ec939cb730
Reviewed-on: https://skia-review.googlesource.com/5645
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2 files changed