Assigning to `size` called our intrinsic sizing functions re-entrantly, which
is a destructive operation on TextPainter. Ideally we'd made that a
non-destructive operation, but in the meantime we can fix the tab fading issue
by grabbing the text size before assigning to `size`.

Fixes #4365

It's safe to remove the unneeded `void`s from setters since the blocking issues in the
`always_declare_return_types` lint have been fixed (https://github.com/dart-lang/linter/).  We can also safely flip the bit on  `avoid_return_types_on_setters`.

TextAlign applies to a whole paragraph instead of applying to an individual
text span. This patch moves the property out of TextStyle and into a separate
property on Text and RichText.

Instead of using properties, TextPainter now receives min and max width as
parameters to layout. Also, this patch integrates the intrinsic sizing logic
into the main layout function, which satisfies all the existing uses cases.

Fixes #3503

We're getting back to the point where we have a bunch of foundation APIs
and it's getting confusing having them mixed with services/.

Fixes #1541

We'll eventually remove Paragraph#paint.

Fixes #2694

And fix the zillion issues that uncovered.

This reverts commit f41b3411, reversing
changes made to e33d8d96.

This was a bad check-in due to my mangling uploading a new version of the branch from a different machine.

This reverts https://github.com/flutter/flutter/pull/2639 and will be replaced by https://github.com/flutter/flutter/pull/2640

And fix the zillion issues that uncovered.

Specifically:

* Handle null styles in TextSpan without crashing in toString().

* Handle null children in TextSpan child lists without crashing in
  toString().

* Handle entirely empty TextSpans in toString() explicitly.

* Assert that TextSpans don't contain nulls in various places. This is
  done more often than one might think necessary, because it turns out
  that TextSpan takes a (mutable) List for one of its arguments, so
  who knows what it will contain at any given time. By asserting all
  over the place, hopefully we'll catch it near the change if they do
  change it.

* Add a RichText example to Stocks to exercise RichText and TextSpans.

See also: https://github.com/flutter/flutter/issues/2514, https://github.com/flutter/flutter/issues/2519

Currently the interface for recognizing gestures on text spans is pretty ugly,
but hopefully we can improve it with time.

Fixes #156

We forgot to compare the lengths of the lists.

Now we just have one TextSpan class that handles both simple strings, trees of
children, and styling both. This approach simplifies the interface for most
clients.

This patch also removes StyledText, which was weakly typed and tricky to use
correctly. The replacement is RichText, which is strongly typed and uses
TextSpan.

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.

Now the text input control knows how to move the caret when you tap
inside the string. There's still some rough edges to polish up, but this
patch is the first step.

Fixes #108

This patch teaches the editing system to paint reasonable selections for
single-line text fields, including for bidirectional text.

Requires https://github.com/flutter/engine/pull/2318

Also, some trivial fixes for things that I found while playing with
the rendering library directly.

The input widget scrolls, so it should give its text loose constraints.  That
way the text ends up being its intrinsic size even if put in a context with
tight constraints.

Fixes #298

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.

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.

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

Fixes #1638

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.

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.

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.