Move the ability to access textures, buffers, and image storages out from GrProcessor.

GrXferProcessor can no longer use this functionality so it is moved to a new intermediate class inherited by GrFragmentProcessor and GrPrimitiveProcessor.

Change-Id: I4f30c89bdceb2d77b602bf0646107e0780881c26
Reviewed-on: https://skia-review.googlesource.com/11202
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
53 files changed