Add new GrContext queries for imagability, surfacability, and max sample count of color types

Bug: skia:7538
Change-Id: I235fc1aa947ba57faa7aef5e7e7ce9241b315fff
Reviewed-on: https://skia-review.googlesource.com/99704
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
7 files changed