Start of cross process SkScalerContext.

Change-Id: I16d9293cbc0bef1bdce1260d1bd9b43d8853d070
Reviewed-on: https://skia-review.googlesource.com/93641
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Herb Derby <herb@google.com>
7 files changed