Remove SkICC::WriteToICC

All clients are using SkWriteICCProfile, which uses types that are more
consistent with the rest of Skia's colorspace API.

Bug: skia:
Change-Id: I1a416027839be95f51a8cabf5dd5d4395cbd2ec6
Reviewed-on: https://skia-review.googlesource.com/c/188636
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>