Add genIDs from all contributing elements to GrReducedClip's mask key.

Change-Id: I3fed124ba3fefd1ef82acdb4ace9531d0c89ad8b
Reviewed-on: https://skia-review.googlesource.com/138586
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
11 files changed