This reverts commit 55f9145e.

Turns out that this commit breaks apps that use the material library,
because of the _errorTextStyle DefaultTextStyle which has inherit:true.
Just setting it to false doesn't work, unfortunately, because then you
hit some sort of issue with merging that text style with others that
have inherit:true.

To make it clear that this constructor requires an explicit style. Also
throw a descriptive error recommending the inherit constructor for
styles with the inherit bit set.

Fixes #3842

Fixes #3759

Previously it used Block, which is less efficient for large numbers of items.
Also move the top margin out of the menu item to fix the baseline alignment of
the text.

Fixes #1615

This patch sizes the menu such that it is always on screen, but doesn't scroll
the menu to ensure that the currently selected item is always visible and on
top of the button. That will need to wait for a later patch.

Also, teach CustomPaint how to repaint animations more efficiently.

Fixes #3720

Clients of getPosition should just use a one-child custom layout delegate
instead.

Fixes #2484

Making progress towards document all public APIs in material.dart. We're still
missing a few odds and ends (as well as missing docs in tabs.dart,
tooltip.dart, and two_level_list.dart).

Fixes #3501

* Gallery code snippets now analyzed

+ Add new demo to gallery to show data tables. (This currently doesn't
use a Card; I'll create a Card version in a subsequent patch.)

+ Fix checkbox alignment. It now centers in its box regardless.

+ Add Colors.black54.

+ Some minor fixes to dartdocs.

+ DataTable, DataColumn, DataRow, DataCell

+ RowInkWell

+ Augment dartdocs of materia/debug.dart.

+ DropDownButtonHideUnderline to hide the underline in a drop-down when
  used in a DataTable.

+ Add new capabilities to InkResponse to support RowInkWell.

+ Augment dartdocs of materia/material.dart.

+ Add an assert to catch nested Blocks.

+ Fix a crash in RenderBox when you remove an object and an ancestor
  used its baseline. (https://github.com/flutter/flutter/issues/2874)

+ Fix (and redocument) RenderBaseline/Baseline.

+ Add flex support to IntrinsicColumnWidth.

+ Document more stuff on the RenderTable side.

+ Fix a bug with parentData handling on RenderTable children.

+ Completely rewrite the column width computations. The old logic made
  no sense at all.

+ Add dartdocs to widgets/debug.dart.

+ Add a toString for TableRow.

Also, clean up a few interfaces that looked awkward when writing docs.

Previously we weren't padding the top and the bottom of drop-down menus but the

spec says these should have 8.0 pixel of padding, the same as popup menus.



Fixes #2683

Therefore, we use _ between them in the file name.

Also, fill out other documentation for these widgets.

Fixes #967

Fixes #617

Adds some names for common FractionalOffset values.

This patch adds a consistent, simple description for the common pattern of
having a single child widget.

* justifyContent -> mainAxisAlignment
* alignItems -> crossAxisAlignment
* FlexJustifyContent -> MainAxisAlignment
* FlexAlignItems -> CrossAxisAlignment

Fixes #231

This patch renames StatelessComponent to StatelessWidget and
StatefulComponent to StatefulWidget.

Fixes #2308

Fixes #1382

Fixes #1278

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.

Fixes https://github.com/flutter/flutter/issues/2436

Rather than managing all the Material Design icons manually, we now
manage them using an icon font. The icon font contains glyphs for each
icon in an efficient vector format.

This patch updates the FLX tooling to include the MaterialIcons font and
updates the Icon widget to use the font instead of asset images.

Fixes #2313
Fixes #2218
Fixes #2009
Fixes #994

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.

This patch removes Performance and AnimationValue now that we've ported the
framework over to AnimationController and Tween. This patch also cleans up the
names of the AnimationController classes now that they don't have to avoid
conflicts with the old animation API. Specifically, I've made the following
renames:

 * Animated -> Animation
 * Evaluatable -> Animatable
 * PerformanceStatus -> AnimationStatus

This patch is just renames and moving code around. There aren't any changes in
behavior.

Providing a pre-built child is more efficient because we don't need to rebuild
the child every tick of the animation.

This patch moves Navigator and related code over to using
AnimationController.

Also, clean up the class hierarchy for AnimationController now that
we've renamed progress to value. That means everything in the hierarchy
now has a value, include Watchable. This patch renames Watchable to
Animated<T>, which lets us use that type almost everywhere.

I've added some ducktape to modal bottom sheets to avoid having to
refactor all of Navigator to use AnimationController. I'll remove the
ducktape in the next patch.

Previously we used a positional argument for widgets that had multiple
children. Now we use a named argument that defaults to an empty list.

Fixes #241

Previously we didn't distinguish between canceling the menu (which
popped the route with no return value, i.e. null) and explicitly
selecting an item whose value is null (pop with value null). Both fired
onChange(null).

Now we box the return value so we can distinguish the two cases.

I would have preferred to just disallow "null" as a value but it turns
out people like being able to use "null" as a value for much the same
reason we do, and it seems best for us to pay the complexity cost of
boxing than having everyone else do it. :-)

Fixes https://github.com/flutter/flutter/issues/948.
I hope.

After this patch, if you try to use a widget that depends on being enclosed in
a material, you now get an assert and a debugPrint if you're not inside a
material.

Fixes #243

Factor out a reusable interface called Decoration from BoxDecoration.

Make all the consumers of BoxDecoration and the erstwhile BoxPainter
into consumers of Decoration.

Make a BoxPainter be something you get from a Decoration, rather than
something to which you pass a BoxDecoration.

Rename Shape to BoxShape now that it's documented specifically as
applying to boxes.

Move EdgeDims to its own file.

Move FractionalOffset up so that it's with the other helper classes in
its file rather than alone at the end.

Minor change to RenderClipOval's hit testing to avoid taking an
unnecessary square root.

Rename BoxDecorationPosition to DecorationPosition since
RenderDecoratedBox now takes any Decoration.

Implement hit testing for rounded rects.

Rename AnimatedBoxDecorationValue to AnimatedDecorationValue, and make
it support lerping across any Decoration (by deferring to the objects
involved).

Now use use the route's getPosition function to position the drop-down menu.
Also, fix a number of other related bugs that blocked the dropdown button from
working correctly. The dropdown menu still has the following issues:

1) In the exit animation, the background of the menu disappears too quickly
   because of incorrect paint bounds computations in the layer tree.
2) The drop down menu isn't positioned correctly after the device rotates.
   We'll need to address this issue in a separate patch.

Fixes #630