Make SkImageCacherator be deferred (take 2)

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

This is a second pass at: https://skia-review.googlesource.com/c/9945/ (Make SkImageCacherator be deferred)

Change-Id: I3451383eed497d1235686e8961087859c7c7bd30
Reviewed-on: https://skia-review.googlesource.com/10034
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
7 files changed