Prepare to enable explicit gpu resource allocation (take 2)

Change-Id: I3fd78d53e8bea84c0217b9fe6e180eaa9e4ac753
Reviewed-on: https://skia-review.googlesource.com/68920
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
11 files changed