Remove compressed texture support from cacherator

All variants of (on)?[rR]efEncoded(Data)? no longer need a GrContext
parameter.

Bug: skia:5485 skia:4971
Change-Id: If4f5e785718d5522eb3df8588318ccb8a02a5749
Reviewed-on: https://skia-review.googlesource.com/14269
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
13 files changed