move SkDraw.h to core

BUG=skia:

Change-Id: Ic8c949530414f3f8d7caded969941dc853a06271
Reviewed-on: https://skia-review.googlesource.com/6845
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed