We still use special-purpose typedefs in the gesture code for symmetry with
other gesture callbacks.

Fixes #1827

We were assuming that the text extended from 0.0 to its max content width.
That's not correct for right-aligned text. Instead, we need to layout the text
again at the width we want it to occupy.

Now TextStyle has a boolean "inherit" value, which controls whether null values
should use should inherit from the current default text style or whether they
should use their initial values.

Also, delete all references to DOM APIs.

The NewTextPainter is still disabled by default. A future patch will flip the
flag to enable it.

This patch uses a new approach to writing bindings by encoding data into array
buffers. This approach is more efficient than the existing IDL based approach.
If this works out well, we should convert our other performance-sensitive
interfaces to this approach in future patches.

Instead of requiring clients to use ui.ColorFilter, we show show the
ColorFilter class, similar to what we do for Color.

It turns out that an AnimatedContainer with a BoxDecoration would
start animating every single time it was built, whether or not the
container's decoration had changed.

We now just use Dart properties, which is more idiomatic.

The goal is to follow the guidelines in
https://github.com/flutter/engine/blob/master/sky/specs/style-guide.md#packages

Fixes #1638

It's OK to just specify the colors list.

Teach dumpRenderTree() to draw actual trees.
Make the TextStyle output terser so it doesn't overflow the output.
Make debugDumpApp() say what mode we're in (checked vs release).
Hide lifecycle state from release mode dumps (since it's checked-only state).

We had a typo in our CSS translation.

This lets you draw nine-patch images.

Add type annotations in many places.
Fix some identifiers to have more lint-satisfying names.
Make all operator==s consistent in style.
Reorder some functions for consistency.
Make ParentData no longer dynamic, and fix all the code around that.

This patch makes it easier to experiment with work on ParagraphBuilder.

MaterialApp assumes that you're using material design.

Also move radial reaction and fix imports for stats box.

Now that you import a top-level file for each layer of the Flutter
framework, within the framework we can use relative paths without being
worried about the copy/pasta problem we used to have.

Fixes #1170

- Rename EdgeDims constructor to EdgeDims.TRBL().

- Add operator== to Size and Offset so that you can compare Size to
  DebugSize in checked mode.

- Add Size.lerp().

- Add various operators to EdgeDims. (*, /, ~/, %)

- Add EdgeDims.lerp().

- Update style guide. I went there to fix an EdgeDims constructor
  example, and stayed because some recent things came up and I wanted to
  add them before I forgot.

AnimationPerformance had some logic for supporting multiple variables
that was hardly ever used. ValueAnimation, a subclass, has logic for
handling a single variable. I've removed the logic for handling
variables from AnimationPerformance in favour of most call sites instead
using ValueAnimation.

EditableText is now rendered using a custom RenderObject
(RenderEditableParagraph).  RenderEditableParagraph draws the cursor,
handles scroll offsets, and provides feedback about the size of the text for
use by the scroll behavior.

I've also removed the top-level description of the Sky package. Instead, we
should host that content on flutter.io.

We removed this value from the engine because it's not useful.

What's important about this code is that it's presenting services outside the
VM, not the particular technology used to present the services.

We now expose idiomatic setters for these properties. Eventually we'll remove
the setter functions.

These are now declared in dart:sky as part of ParagraphBuilder.

These files really belong on other libraries.