Move clear-as-draw caps into GrCaps Bug: skia: Change-Id: Ib029f337f5e61366e2550e77dc99310b44d03f84 Reviewed-on: https://skia-review.googlesource.com/c/182970 Reviewed-by: Brian Salomon <bsalomon@google.com> Commit-Queue: Michael Ludwig <michaelludwig@google.com>