Use MatrixRec in legacy shader context code

Bug: skia:14076
Change-Id: I750222f18a1705e9e98ee21a6b4ec22d744b2c03
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/714818
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
8 files changed