GrSurface -> GrGpuBuffer transfer improvements:

GrCaps now only provides the offset alignment requirement. The row bytes
is always bpp * width.

GrGpu::transferPixelsFrom now just returns bool since row bytes value is
implicit. It now asserts offset is aligned with GrCap's provided value
in base class.

Implement caps for GL.

Bug: skia:8962
Change-Id: I3299b62efe9fe05bfe02f2a6a4c2704f647d0f8a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206686
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
18 files changed