Avoid redrawing every time the mouse moves

Bug: skia:
Change-Id: Idc74e6c7e50f8d416d716ee666b37b52792c7c4b
Reviewed-on: https://skia-review.googlesource.com/87789
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed