There are a few places where we still have an incorrect PaintImage::Id discardable images captured in cc. These include:

1) SkImageShaders: This will require replacing the use of these shaders themselves.

2) ImageHijackCanvas: This should be simple since we can capture images from the PaintOpBuffer itself instead of having to go through an SkNWayCanvas.

3) LayerTreeHost: The QueueImageDecode API needs to receive a PaintImage instead of SkImage.