* Roll the engine.

This engine includes a VM that defaults to sync-async.

flutter/engine@c8eeee4 Roll the Dart VM.

Adds a test that verifies that the microtask queue is flushed between
engine event loop iterations.

Related issue: https://github.com/flutter/flutter/issues/9998

Instead of using getTotalMatrix and setMatrix, we can just use
save/restore, which is more idiomatic.

The getTotalMatrix/setMatrix pattern was introduced to improve
performance, but the original code was calling getTotalMatrix/setMatrix
at every node in the sprite tree, which is much slower than the normal
save/transform/restore pattern.

Related to #4254

Turns out there were more clients of the old paragraph API than I expected.
This patch migrates them to the new API.

See https://github.com/flutter/flutter/issues/1854

I'm guessing the recent changes to the bindings fixed this crash.

Closes https://github.com/flutter/flutter/issues/248.

Each layer is supposed to reexport the parts of the previous layer
that are part of its API.

- In painting.dart, export from dart:ui all the Canvas-related APIs
  that make sense to be used at higher levels, e.g. PaintingStyle.

- Delete painting/shadows.dart. It was dead code.

- In rendering/object.dart, export all of painting.dart.

- In widgets/basic.dart, export all of painting.dart and
  animation.dart. Some classes in animation/ are renamed to make this
  less disruptive and confusing to the namespace.

- Split out Stocks back into an import model rather than a part model,
  so that it's easier to manage its dependencies on a per-file basis.

- Move Ticker to scheduler library.

- Remove as many redundant imports as possible now.

- Some minor nit picking cleanup in various files.