Consolidate more shadow generation code.

Moves the spot shadow code into the base class, and has both shadow
types use it to generate their geometry.

Bug: skia:7971
Change-Id: I866aa8a8a796a5f4bbf4698e1df5148c547ee3c2
Reviewed-on: https://skia-review.googlesource.com/152662
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
1 file changed