This is less to type in most cases, and gives us more information
(for things like picture-backed images, where we need to know all
about the destination surface).
Additionally, strip out the plumbing entirely for bitmap sources,
where we don't need to know anything.
BUG=skia:
Change-Id: I4deff6c7c345fcf62eb08b2aff0560adae4313da
Reviewed-on: https://skia-review.googlesource.com/5748
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
61624f0c71