Bump min picture to 7+ months ago

Delete lots of support code, including need for SkXfermode objects
which are no longer used anywhere else.

Bug: skia:
Change-Id: Id6b7ef0f529691041ff2b206c35e336e8a4c974d
Reviewed-on: https://skia-review.googlesource.com/19059
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
13 files changed