Clean up xfermodes3 gm.

Update temporary surface creation so that cpu and gpu are doing the same
thing, reducing confusion around what the test is doing.

Also clip to the bounds of the saved layer when a temporary surface cannot
be created. This prevents the underspecified behavior of drawing outside
the bounds of a saved layer.

Change-Id: Iad35b394f50b4e1867a8bffdc9f5b3d2ae9c1645
Reviewed-on: https://skia-review.googlesource.com/123741
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed