specialize D32 proc for legacy src

lots of dead-code removal

Bug: skia:
Change-Id: I23ea25eb38855b4776e97fa8ff777d9744baab1d
Reviewed-on: https://skia-review.googlesource.com/19147
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
10 files changed