Remove asTextureRef from SkSpecialImage & update effects accordingly (take 2)

This CL also renames SkSpecialImage::asTextureProxy to asTextureProxyRef

This is a reland of: https://skia-review.googlesource.com/c/7995/ (Remove asTextureRef from SkSpecialImage & update effects accordingly)

It should be good to land since https://skia-review.googlesource.com/c/8701/ (Replace SkSpecialImage::makeTightSubset with asImage (take 2)) fixes the Chrome-side issue

Change-Id: I3d88b2b3d23fd69f3fb914a69dacca96cbc038a4
Reviewed-on: https://skia-review.googlesource.com/8450
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
17 files changed