Switch SkPaint's color to SkColor4f

Change-Id: Ic2b83a05739720013a7c30ec014df0747b3f99a5
Reviewed-on: https://skia-review.googlesource.com/149229
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
9 files changed