Remove SkImageCacherator entirely

It was just the slice of SkImage_Lazy's API that we needed to expose to
GrImageTextureMaker. Instead, give SkImage_Lazy a header, so that the
maker can use it directly.

Change-Id: Iea6198f63e8065b8c987f7c07f3222409cdda439
Reviewed-on: https://skia-review.googlesource.com/153546
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
9 files changed