This CL adds the GrBackend* classes as well as just updates the API for SkSurface and
SkImage. The implementation on SkSurface/Image and the plumbing down into Ganesh will
be in an additional CL.
Besides the change to use the type safe classes, we also pull the SurfaceFlags, origin,
samples, out of the descriptor and pass those in directly.
Bug: skia:
Change-Id: I9702981fe26c3d5d7d2cbcf6977ba569d356d854
Reviewed-on: https://skia-review.googlesource.com/13122
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
