remove unneeded friends/includes in SkPaint.h

Bug: skia:
Change-Id: Ica9f10cdb67322eb43ec38b6549146350fa5dcd9
Reviewed-on: https://skia-review.googlesource.com/c/188630
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
11 files changed