sksl support for static ifs & switches

Bug: skia:
Change-Id: Ic9e01a3a18efddb19bab26e92bfb473cad294fc1
Reviewed-on: https://skia-review.googlesource.com/16144
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
17 files changed