This also includes adding drawable Op and plumbing it through to the GPU.
BUG=skia:
Change-Id: I0b2464c5a458c2fbf05b9528e47b9e6e3ac27d57
Reviewed-on: https://skia-review.googlesource.com/c/9645
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
