Remove a few GrSurfaceProxy::config() usages

Change-Id: I9da9e1dadea71701c97994f8df1e7b5912989672
Bug: skia:6718
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/243159
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
5 files changed