Make SkImageCacherator be deferred

Split out of: https://skia-review.googlesource.com/c/8823/ (Remove GrFragmentProcessor-derived class' GrTexture-based ctors)

Change-Id: I16cf0aea9d887e5ebe053e9b5c94a970dc254beb
Reviewed-on: https://skia-review.googlesource.com/9945
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
6 files changed