turn on force_opaque for opaque devices

Change-Id: I517be3182745baaff539cfd24dd47df4c17e24d9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/232820
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
1 file changed