Remove GrYUVProvider.

This abstraction had one subclass. That subclass was used only as
an implementation detail of SkImage_Lazy. Move the functionality
into SkImage_Lazy.

Change-Id: Icd8754114dc33ae957e542b372086e8caa0408a3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/305724
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
7 files changed