Revert "Revert "Add support for gray + colorspace to SkCodec""

This reverts commit a51d1b45a3c12f5b3c5a4e04800b0abe57e999fe.

Bug: skia:
Change-Id: I9536dc32e9616c700445a996264ef811f131b6e9
Reviewed-on: https://skia-review.googlesource.com/150913
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
5 files changed