Add SkColorType getter on SkImage.

Bug: skia:
Change-Id: I131fb5f7faf3f54e0eb6d31b800d224e6d4963ce
Reviewed-on: https://skia-review.googlesource.com/114464
Reviewed-by: Cary Clark <caryclark@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
8 files changed