Previously we just dropped child scenes on the floor. Now we upload them
to Mozart. However, we just draw them on top of all the other content
and don't apply any clips or blends.
After an application is suspended and the GrContext associated with the
Flutter view is destroyed, the raster cache still contains images tied
to the defunct context. The SkyShell process will crash if these images
are used after the application resumes.
This patch contains Dart bindings for adding a child scene when running in
Mozart. The child scene is currently ignored, but a later patch will actually
incoporate it into the tree.
When rasterzing with a non-zero left and top offset, we need to apply the scale
first so that we're translating in the correct coordinate system.
Fixes https://github.com/flutter/flutter/issues/1292
The matrix argument to drawPicture doesn't seem to do what we want exactly.
Instead, use the normal matrix in the canvas. Also, handle cull rects with
non-zero left and top coordinates.
Fixes#1229
