bug:20063841
Restores old SkShader matrix behavior from before the Glop refactor.
Many drawing operations draw without sending the canvas transform to
the GL shader. In such cases, we need to adapt the matrix sent to the
SkShader logic to invert the canvas transform that's built into
the mesh.
Change-Id: I42b6f59df36ce46436322b95bf9ad2140795ee58