Raster pipeline support for SkLocalMatrixShader composition

Plumb a local matrix arg to onAppendStages, similar to onCreateContext's
ContextRec::fLocalMatrix.

Change-Id: I6db3706918733b35eb7a3ae2cc65503223d0cf2d
Reviewed-on: https://skia-review.googlesource.com/7653
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
10 files changed