Implement SkICC::WriteICC()

BUG=skia:

Change-Id: Idd950c3da2c517780b24e312a4e7cc16ee413c99
Reviewed-on: https://skia-review.googlesource.com/6270
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
9 files changed