Reland "pass more information to shaders"

This is a reland of 4f275cfe0e527791d5a2e7b01d714e4dff4ef1d8

Original change's description:
> pass more information to shaders
> 
> If we're going to write an image shader, we're going to need to know the
> matrix and some bits of the paint.
> 
> Instead of all possible information, I decided to pass just what the
> image shader needs for now, and will pass along more as I go.
> 
> I've added a stub implementation of SkImageFilter as a way to make sure
> I'm threading everything it'll need through.
> 
> Change-Id: I98de1724056dbc0902a34fc31da8ec6bdf38dc34
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/261801
> Commit-Queue: Mike Klein <mtklein@google.com>
> Reviewed-by: Mike Reed <reed@google.com>

Change-Id: I2541903ad559fe8b584e46b1e9d68ec804b7a15d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/261779
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
10 files changed