extend savelayer_maskfilter to also have an imagefilter

Bug: skia:7597
Change-Id: I8af9c9f841c301212a4a452f9b42d03a20e36417
Reviewed-on: https://skia-review.googlesource.com/105220
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed