To view progress on Flutter GPU, see this dashboard!

This is an umbrella bug that links to all other issues required for a Flutter GPU MVP.

MVP means: With a production Impeller backend enabled, users can...

• import from package:flutter_gpu, shipped as a built-in Flutter SDK package
• import shader bundles defined in pubspec.yaml
• explicitly allocate textures (or other surface derivative, like swapchains)
• import shader bundle assets and use them to form pipelines
• schedule the execution of render passes against those texture(s)
• instruct Flutter to composite those textures into the 2D Flutter scene