RTL: Padding, Flex (#11709)

* Introduce a Directionality inherited widget which sets the ambient LTR vs RTL mode (defaulting to null, which means you cannot use directionality-influenced values).

* Make it possible to configure Padding (including Container.padding and Container.margin) using a directionality-agnostic EdgeInsets variant.

* Provide textDirection and verticalDirection controls on Row and Column to make them RTL-aware.

* Introduce a variant of FractionalOffset based on the EdgeInsets variant. Not yet actually used.

* Fix all the tests that depended on Row defaulting to LTR.

examples/layers/test/gestures_test.dart

@@ -9,7 +9,10 @@ import '../widgets/gestures.dart';
 
 void main() {
   testWidgets('Tap on center change color', (WidgetTester tester) async {
-    await tester.pumpWidget(new GestureDemo());
+    await tester.pumpWidget(new Directionality(
+      textDirection: TextDirection.ltr,
+      child: new GestureDemo(),
+    ));
     final Finder finder = find.byType(GestureDemo);
 
     MaterialColor getSwatch() => tester.state<GestureDemoState>(finder).swatch;

packages/flutter/lib/src/material/app.dart

@@ -26,11 +26,14 @@ const TextStyle _errorTextStyle = const TextStyle(
   decorationStyle: TextDecorationStyle.double
 );
 
+// Delegate that fetches the default (English) strings.
 class _MaterialLocalizationsDelegate extends LocalizationsDelegate<MaterialLocalizations> {
   const _MaterialLocalizationsDelegate();
 
   @override
-  Future<MaterialLocalizations> load(Locale locale) => MaterialLocalizations.load(locale);
+  Future<MaterialLocalizations> load(Locale locale) {
+    return new SynchronousFuture<MaterialLocalizations>(const MaterialLocalizations());
+  }
 
   @override
   bool shouldReload(_MaterialLocalizationsDelegate old) => false;
@@ -317,8 +320,8 @@ class _MaterialAppState extends State<MaterialApp> {
 
   // Combine the Localizations for Material with the ones contributed
   // by the localizationsDelegates parameter, if any.
-  Iterable<LocalizationsDelegate<dynamic>> _createLocalizationsDelegates() sync* {
-    yield const _MaterialLocalizationsDelegate();
+  Iterable<LocalizationsDelegate<dynamic>> get _localizationsDelegates sync* {
+    yield const _MaterialLocalizationsDelegate(); // TODO(ianh): make this configurable
     if (widget.localizationsDelegates != null)
       yield* widget.localizationsDelegates;
   }
@@ -397,7 +400,7 @@ class _MaterialAppState extends State<MaterialApp> {
         onGenerateRoute: _onGenerateRoute,
         onUnknownRoute: _onUnknownRoute,
         locale: widget.locale,
-        localizationsDelegates: _createLocalizationsDelegates(),
+        localizationsDelegates: _localizationsDelegates,
         showPerformanceOverlay: widget.showPerformanceOverlay,
         checkerboardRasterCacheImages: widget.checkerboardRasterCacheImages,
         checkerboardOffscreenLayers: widget.checkerboardOffscreenLayers,

packages/flutter/lib/src/material/chip.dart

@@ -106,16 +106,16 @@ class Chip extends StatelessWidget {
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final bool deletable = onDeleted != null;
-    double leftPadding = 12.0;
-    double rightPadding = 12.0;
+    double startPadding = 12.0;
+    double endPadding = 12.0;
 
     final List<Widget> children = <Widget>[];
 
     if (avatar != null) {
-      leftPadding = 0.0;
+      startPadding = 0.0;
       children.add(new ExcludeSemantics(
         child: new Container(
-          margin: const EdgeInsets.only(right: 8.0),
+          margin: const EdgeInsetsDirectional.only(end: 8.0),
           width: _kAvatarDiamater,
           height: _kAvatarDiamater,
           child: avatar,
@@ -131,7 +131,7 @@ class Chip extends StatelessWidget {
     ));
 
     if (deletable) {
-      rightPadding = 0.0;
+      endPadding = 0.0;
       children.add(new GestureDetector(
         onTap: Feedback.wrapForTap(onDeleted, context),
         child: new Tooltip(
@@ -152,7 +152,7 @@ class Chip extends StatelessWidget {
       container: true,
       child: new Container(
         height: _kChipHeight,
-        padding: new EdgeInsets.only(left: leftPadding, right: rightPadding),
+        padding: new EdgeInsetsDirectional.only(start: startPadding, end: endPadding),
         decoration: new BoxDecoration(
           color: backgroundColor ?? Colors.grey.shade300,
           borderRadius: new BorderRadius.circular(16.0),

packages/flutter/lib/src/material/material_localizations.dart

@@ -2,29 +2,35 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
-import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 
-/// Default localized resource values for the material widgets.
+/// Interface for localized resource values for the material widgets.
 ///
-/// This class is just a placeholder, it only provides English values.
+/// This class provides a default placeholder implementation that returns
+/// hard-coded American English values.
 class MaterialLocalizations {
-  const MaterialLocalizations._(this.locale) : assert(locale != null);
+  /// Create a placeholder object for the localized resources of material widgets
+  /// which only provides American English strings.
+  const MaterialLocalizations();
 
   /// The locale for which the values of this class's localized resources
   /// have been translated.
-  final Locale locale;
+  Locale get locale => const Locale('en', 'US');
 
-  /// Creates an object that provides default localized resource values for the
-  /// for the widgets of the material library.
-  ///
-  /// This method is typically used to create a [DefaultLocalizationsDelegate].
-  /// The [MaterialApp] does so by default.
-  static Future<MaterialLocalizations> load(Locale locale) {
-    return new SynchronousFuture<MaterialLocalizations>(new MaterialLocalizations._(locale));
-  }
+  /// The tooltip for the leading [AppBar] menu (aka 'hamburger') button
+  String get openAppDrawerTooltip => 'Open navigation menu';
+
+  /// The [BackButton]'s tooltip.
+  String get backButtonTooltip => 'Back';
+
+  /// The [CloseButton]'s tooltip.
+  String get closeButtonTooltip => 'Close';
+
+  /// The tooltip for the [MonthPicker]'s "next month" button.
+  String get nextMonthTooltip => 'Next month';
+
+  /// The tooltip for the [MonthPicker]'s "previous month" button.
+  String get previousMonthTooltip => 'Previous month';
 
   /// The `MaterialLocalizations` from the closest [Localizations] instance
   /// that encloses the given context.
@@ -34,25 +40,11 @@ class MaterialLocalizations {
   ///
   /// References to the localized resources defined by this class are typically
   /// written in terms of this method. For example:
+  ///
   /// ```dart
   /// tooltip: MaterialLocalizations.of(context).backButtonTooltip,
   /// ```
   static MaterialLocalizations of(BuildContext context) {
     return Localizations.of<MaterialLocalizations>(context, MaterialLocalizations);
   }
-
-  /// The tooltip for the leading [AppBar] menu (aka 'hamburger') button
-  String get openAppDrawerTooltip => 'Open navigation menu';
-
-  /// The [BackButton]'s tooltip.
-  String get backButtonTooltip => 'Back';
-
-  /// The [CloseButton]'s tooltip.
-  String get closeButtonTooltip => 'Close';
-
-  /// The tooltip for the [MonthPicker]'s "next month" button.
-  String get nextMonthTooltip => 'Next month';
-
-  /// The tooltip for the [MonthPicker]'s "previous month" button.
-  String get previousMonthTooltip => 'Previous month';
 }

packages/flutter/lib/src/material/tabs.dart

@@ -150,6 +150,8 @@ class _TabLabelBarRenderer extends RenderFlex {
     MainAxisSize mainAxisSize,
     MainAxisAlignment mainAxisAlignment,
     CrossAxisAlignment crossAxisAlignment,
+    TextDirection textDirection,
+    VerticalDirection verticalDirection,
     TextBaseline textBaseline,
     @required this.onPerformLayout,
   }) : assert(onPerformLayout != null),
@@ -159,6 +161,8 @@ class _TabLabelBarRenderer extends RenderFlex {
          mainAxisSize: mainAxisSize,
          mainAxisAlignment: mainAxisAlignment,
          crossAxisAlignment: crossAxisAlignment,
+         textDirection: textDirection,
+         verticalDirection: verticalDirection,
          textBaseline: textBaseline,
        );
 
@@ -188,6 +192,8 @@ class _TabLabelBar extends Flex {
     Key key,
     MainAxisAlignment mainAxisAlignment,
     CrossAxisAlignment crossAxisAlignment,
+    TextDirection textDirection,
+    VerticalDirection verticalDirection: VerticalDirection.down,
     List<Widget> children: const <Widget>[],
     this.onPerformLayout,
   }) : super(
@@ -197,6 +203,8 @@ class _TabLabelBar extends Flex {
     mainAxisSize: MainAxisSize.max,
     mainAxisAlignment: MainAxisAlignment.start,
     crossAxisAlignment: CrossAxisAlignment.center,
+    textDirection: textDirection,
+    verticalDirection: verticalDirection,
   );
 
   final ValueChanged<List<double>> onPerformLayout;
@@ -208,6 +216,8 @@ class _TabLabelBar extends Flex {
       mainAxisAlignment: mainAxisAlignment,
       mainAxisSize: mainAxisSize,
       crossAxisAlignment: crossAxisAlignment,
+      textDirection: getEffectiveTextDirection(context),
+      verticalDirection: verticalDirection,
       textBaseline: textBaseline,
       onPerformLayout: onPerformLayout,
     );

packages/flutter/lib/src/painting/basic_types.dart

@@ -90,3 +90,70 @@ enum RenderComparison {
   /// change in a render object.
   layout,
 }
+
+/// The two cardinal directions in two dimensions.
+///
+/// The axis is always relative to the current coordinate space. This means, for
+/// example, that a [horizontal] axis might actually be diagonally from top
+/// right to bottom left, due to some local [Transform] applied to the scene.
+///
+/// See also:
+///
+///  * [AxisDirection], which is a directional version of this enum (with values
+///    light left and right, rather than just horizontal).
+///  * [TextDirection], which disambiguates between left-to-right horizontal
+///    content and right-to-left horizontal content.
+enum Axis {
+  /// Left and right.
+  ///
+  /// See also:
+  ///
+  ///  * [TextDirection], which disambiguates between left-to-right horizontal
+  ///    content and right-to-left horizontal content.
+  horizontal,
+
+  /// Up and down.
+  vertical,
+}
+
+/// Returns the opposite of the given [Axis].
+///
+/// Specifically, returns [Axis.horizontal] for [Axis.vertical], and
+/// vice versa.
+///
+/// See also:
+///
+///  * [flipAxisDirection], which does the same thing for [AxisDirection] values.
+Axis flipAxis(Axis direction) {
+  assert(direction != null);
+  switch (direction) {
+    case Axis.horizontal:
+      return Axis.vertical;
+    case Axis.vertical:
+      return Axis.horizontal;
+  }
+  return null;
+}
+
+/// A direction in which boxes flow vertically.
+///
+/// This is used by the flex algorithm (e.g. [Column]) to decide in which
+/// direction to draw boxes.
+///
+/// This is also used to disambiguate `start` and `end` values (e.g.
+/// [MainAxisAlignment.start] or [CrossAxisAlignment.end]).
+///
+/// See also:
+///
+///  * [TextDirection], which controls the same thing but horizontally.
+enum VerticalDirection {
+  /// Boxes should start at the bottom and be stacked vertically towards the top.
+  ///
+  /// The "start" is at the bottom, the "end" is at the top.
+  up,
+
+  /// Boxes should start at the top and be stacked vertically towards the bottom.
+  ///
+  /// The "start" is at the top, the "end" is at the bottom.
+  down,
+}

packages/flutter/lib/src/rendering/box.dart

@@ -2149,6 +2149,11 @@ abstract class RenderBoxContainerDefaultsMixin<ChildType extends RenderBox, Pare
   ///
   /// Stops walking once after the first child reports that it contains the
   /// given point. Returns whether any children contain the given point.
+  ///
+  /// See also:
+  ///
+  ///  * [defaultPaint], which paints the children appropriate for this
+  ///    hit-testing strategy.
   bool defaultHitTestChildren(HitTestResult result, { Offset position }) {
     // the x, y parameters have the top left of the node's box as the origin
     ChildType child = lastChild;
@@ -2162,6 +2167,11 @@ abstract class RenderBoxContainerDefaultsMixin<ChildType extends RenderBox, Pare
   }
 
   /// Paints each child by walking the child list forwards.
+  ///
+  /// See also:
+  ///
+  ///  * [defaultHitTestChildren], which implements hit-testing of the children
+  ///    in a manner appropriate for this painting strategy.
   void defaultPaint(PaintingContext context, Offset offset) {
     ChildType child = firstChild;
     while (child != null) {

packages/flutter/lib/src/rendering/node.dart

@@ -43,7 +43,7 @@ class AbstractNode {
   int get depth => _depth;
   int _depth = 0;
 
-  /// Adjust the [depth] of the given [child] to be greated than this node's own
+  /// Adjust the [depth] of the given [child] to be greater than this node's own
   /// [depth].
   ///
   /// Only call this method from overrides of [redepthChildren].

packages/flutter/lib/src/rendering/shifted_box.dart

@@ -91,29 +91,58 @@ class RenderPadding extends RenderShiftedBox {
   ///
   /// The [padding] argument must not be null and must have non-negative insets.
   RenderPadding({
-    @required EdgeInsets padding,
-    RenderBox child
+    @required EdgeInsetsGeometry padding,
+    TextDirection textDirection,
+    RenderBox child,
   }) : assert(padding != null),
        assert(padding.isNonNegative),
+       _textDirection = textDirection,
        _padding = padding,
-       super(child);
+       super(child) {
+    _applyUpdate();
+  }
+
+  // The resolved absolute insets.
+  EdgeInsets _resolvedPadding;
+
+  void _applyUpdate() {
+    final EdgeInsets resolvedPadding = padding.resolve(textDirection);
+    assert(resolvedPadding.isNonNegative);
+    if (resolvedPadding != _resolvedPadding) {
+      _resolvedPadding = resolvedPadding;
+      markNeedsLayout();
+    }
+  }
 
   /// The amount to pad the child in each dimension.
-  EdgeInsets get padding => _padding;
-  EdgeInsets _padding;
-  set padding(EdgeInsets value) {
+  ///
+  /// If this is set to an [EdgeInsetsDirectional] object, then [textDirection]
+  /// must be non-null.
+  EdgeInsetsGeometry get padding => _padding;
+  EdgeInsetsGeometry _padding;
+  set padding(EdgeInsetsGeometry value) {
     assert(value != null);
     assert(value.isNonNegative);
     if (_padding == value)
       return;
     _padding = value;
-    markNeedsLayout();
+    _applyUpdate();
+  }
+
+  /// The text direction with which to resolve [padding].
+  TextDirection get textDirection => _textDirection;
+  TextDirection _textDirection;
+  set textDirection(TextDirection value) {
+    if (_textDirection == value)
+      return;
+    _textDirection = value;
+    _applyUpdate();
   }
 
   @override
   double computeMinIntrinsicWidth(double height) {
-    final double totalHorizontalPadding = padding.left + padding.right;
-    final double totalVerticalPadding = padding.top + padding.bottom;
+    final double totalHorizontalPadding = _resolvedPadding.left + _resolvedPadding.right;
+    final double totalVerticalPadding = _resolvedPadding.top + _resolvedPadding.bottom;
     if (child != null) // next line relies on double.INFINITY absorption
       return child.getMinIntrinsicWidth(math.max(0.0, height - totalVerticalPadding)) + totalHorizontalPadding;
     return totalHorizontalPadding;
@@ -121,8 +150,8 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   double computeMaxIntrinsicWidth(double height) {
-    final double totalHorizontalPadding = padding.left + padding.right;
-    final double totalVerticalPadding = padding.top + padding.bottom;
+    final double totalHorizontalPadding = _resolvedPadding.left + _resolvedPadding.right;
+    final double totalVerticalPadding = _resolvedPadding.top + _resolvedPadding.bottom;
     if (child != null) // next line relies on double.INFINITY absorption
       return child.getMaxIntrinsicWidth(math.max(0.0, height - totalVerticalPadding)) + totalHorizontalPadding;
     return totalHorizontalPadding;
@@ -130,8 +159,8 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   double computeMinIntrinsicHeight(double width) {
-    final double totalHorizontalPadding = padding.left + padding.right;
-    final double totalVerticalPadding = padding.top + padding.bottom;
+    final double totalHorizontalPadding = _resolvedPadding.left + _resolvedPadding.right;
+    final double totalVerticalPadding = _resolvedPadding.top + _resolvedPadding.bottom;
     if (child != null) // next line relies on double.INFINITY absorption
       return child.getMinIntrinsicHeight(math.max(0.0, width - totalHorizontalPadding)) + totalVerticalPadding;
     return totalVerticalPadding;
@@ -139,8 +168,8 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   double computeMaxIntrinsicHeight(double width) {
-    final double totalHorizontalPadding = padding.left + padding.right;
-    final double totalVerticalPadding = padding.top + padding.bottom;
+    final double totalHorizontalPadding = _resolvedPadding.left + _resolvedPadding.right;
+    final double totalVerticalPadding = _resolvedPadding.top + _resolvedPadding.bottom;
     if (child != null) // next line relies on double.INFINITY absorption
       return child.getMaxIntrinsicHeight(math.max(0.0, width - totalHorizontalPadding)) + totalVerticalPadding;
     return totalVerticalPadding;
@@ -148,21 +177,21 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   void performLayout() {
-    assert(padding != null);
+    assert(_resolvedPadding != null);
     if (child == null) {
       size = constraints.constrain(new Size(
-        padding.left + padding.right,
-        padding.top + padding.bottom
+        _resolvedPadding.left + _resolvedPadding.right,
+        _resolvedPadding.top + _resolvedPadding.bottom
       ));
       return;
     }
-    final BoxConstraints innerConstraints = constraints.deflate(padding);
+    final BoxConstraints innerConstraints = constraints.deflate(_resolvedPadding);
     child.layout(innerConstraints, parentUsesSize: true);
     final BoxParentData childParentData = child.parentData;
-    childParentData.offset = new Offset(padding.left, padding.top);
+    childParentData.offset = new Offset(_resolvedPadding.left, _resolvedPadding.top);
     size = constraints.constrain(new Size(
-      padding.left + child.size.width + padding.right,
-      padding.top + child.size.height + padding.bottom
+      _resolvedPadding.left + child.size.width + _resolvedPadding.right,
+      _resolvedPadding.top + child.size.height + _resolvedPadding.bottom
     ));
   }
 
@@ -171,7 +200,7 @@ class RenderPadding extends RenderShiftedBox {
     super.debugPaintSize(context, offset);
     assert(() {
       final Rect outerRect = offset & size;
-      debugPaintPadding(context.canvas, outerRect, child != null ? padding.deflateRect(outerRect) : null);
+      debugPaintPadding(context.canvas, outerRect, child != null ? _resolvedPadding.deflateRect(outerRect) : null);
       return true;
     });
   }
@@ -179,7 +208,8 @@ class RenderPadding extends RenderShiftedBox {
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder description) {
     super.debugFillProperties(description);
-    description.add(new DiagnosticsProperty<EdgeInsets>('padding', padding));
+    description.add(new DiagnosticsProperty<EdgeInsetsGeometry>('padding', padding));
+    description.add(new EnumProperty<TextDirection>('textDirection', textDirection));
   }
 }
 

packages/flutter/lib/src/rendering/sliver.dart

@@ -94,6 +94,10 @@ Axis axisDirectionToAxis(AxisDirection axisDirection) {
 /// Specifically, returns [AxisDirection.up] for [AxisDirection.down] (and
 /// vice versa), as well as [AxisDirection.left] for [AxisDirection.right] (and
 /// vice versa).
+///
+/// See also:
+///
+///  * [flipAxis], which does the same thing for [Axis] values.
 AxisDirection flipAxisDirection(AxisDirection axisDirection) {
   assert(axisDirection != null);
   switch (axisDirection) {

packages/flutter/lib/src/widgets/app.dart

@@ -23,6 +23,19 @@ import 'widget_inspector.dart';
 
 export 'dart:ui' show Locale;
 
+// Delegate that fetches the default (English) strings.
+class _WidgetsLocalizationsDelegate extends LocalizationsDelegate<WidgetsLocalizations> {
+  const _WidgetsLocalizationsDelegate();
+
+  @override
+  Future<WidgetsLocalizations> load(Locale locale) {
+    return new SynchronousFuture<WidgetsLocalizations>(const WidgetsLocalizations());
+  }
+
+  @override
+  bool shouldReload(_WidgetsLocalizationsDelegate old) => false;
+}
+
 /// A convenience class that wraps a number of widgets that are commonly
 /// required for an application.
 ///
@@ -269,6 +282,14 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
     }
   }
 
+  // Combine the Localizations for Widgets with the ones contributed
+  // by the localizationsDelegates parameter, if any.
+  Iterable<LocalizationsDelegate<dynamic>> get _localizationsDelegates sync* {
+    yield const _WidgetsLocalizationsDelegate(); // TODO(ianh): make this configurable
+    if (widget.localizationsDelegates != null)
+      yield* widget.localizationsDelegates;
+  }
+
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) { }
 
@@ -281,7 +302,7 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
       data: new MediaQueryData.fromWindow(ui.window),
       child: new Localizations(
         locale: widget.locale ?? _locale,
-        delegates: widget.localizationsDelegates,
+        delegates: _localizationsDelegates.toList(),
         child: new Title(
           title: widget.title,
           color: widget.color,

packages/flutter/lib/src/widgets/container.dart

@@ -282,7 +282,7 @@ class Container extends StatelessWidget {
 
   /// Empty space to inscribe inside the [decoration]. The [child], if any, is
   /// placed inside this padding.
-  final EdgeInsets padding;
+  final EdgeInsetsGeometry padding;
 
   /// The decoration to paint behind the [child].
   ///
@@ -303,18 +303,18 @@ class Container extends StatelessWidget {
   final BoxConstraints constraints;
 
   /// Empty space to surround the [decoration] and [child].
-  final EdgeInsets margin;
+  final EdgeInsetsGeometry margin;
 
   /// The transformation matrix to apply before painting the container.
   final Matrix4 transform;
 
-  EdgeInsets get _paddingIncludingDecoration {
+  EdgeInsetsGeometry get _paddingIncludingDecoration {
     if (decoration == null || decoration.padding == null)
       return padding;
-    final EdgeInsets decorationPadding = decoration.padding;
+    final EdgeInsetsGeometry decorationPadding = decoration.padding;
     if (padding == null)
       return decorationPadding;
-    return padding + decorationPadding;
+    return padding.add(decorationPadding);
   }
 
   @override
@@ -332,7 +332,7 @@ class Container extends StatelessWidget {
     if (alignment != null)
       current = new Align(alignment: alignment, child: current);
 
-    final EdgeInsets effectivePadding = _paddingIncludingDecoration;
+    final EdgeInsetsGeometry effectivePadding = _paddingIncludingDecoration;
     if (effectivePadding != null)
       current = new Padding(padding: effectivePadding, child: current);
 
@@ -363,11 +363,11 @@ class Container extends StatelessWidget {
   void debugFillProperties(DiagnosticPropertiesBuilder description) {
     super.debugFillProperties(description);
     description.add(new DiagnosticsProperty<FractionalOffset>('alignment', alignment, showName: false, defaultValue: null));
-    description.add(new DiagnosticsProperty<EdgeInsets>('padding', padding, defaultValue: null));
+    description.add(new DiagnosticsProperty<EdgeInsetsGeometry>('padding', padding, defaultValue: null));
     description.add(new DiagnosticsProperty<Decoration>('bg', decoration, defaultValue: null));
     description.add(new DiagnosticsProperty<Decoration>('fg', foregroundDecoration, defaultValue: null));
     description.add(new DiagnosticsProperty<BoxConstraints>('constraints', constraints, defaultValue: null));
-    description.add(new DiagnosticsProperty<EdgeInsets>('margin', margin, defaultValue: null));
+    description.add(new DiagnosticsProperty<EdgeInsetsGeometry>('margin', margin, defaultValue: null));
     description.add(new ObjectFlagProperty<Matrix4>.has('transform', transform));
   }
 }

packages/flutter/lib/src/widgets/localizations.dart

@@ -7,6 +7,7 @@ import 'dart:ui' show Locale;
 
 import 'package:flutter/foundation.dart';
 
+import 'basic.dart';
 import 'binding.dart';
 import 'container.dart';
 import 'framework.dart';
@@ -90,6 +91,47 @@ abstract class LocalizationsDelegate<T> {
   /// rebuilt. If it returns true then dependent widgets will be rebuilt
   /// after [load] has completed.
   bool shouldReload(covariant LocalizationsDelegate<T> old);
+
+  @override
+  String toString() => '$runtimeType';
+}
+
+/// Interface for localized resource values for the lowest levels of the Flutter
+/// framework.
+///
+/// In particular, this maps locales to a specific [Directionality] using the
+/// [textDirection] property.
+///
+/// This class provides a default placeholder implementation that returns
+/// hard-coded American English values.
+class WidgetsLocalizations {
+  /// Create a placeholder object for the localized resources of the lowest
+  /// levels of the Flutter framework which only provides values for American
+  /// English.
+  const WidgetsLocalizations();
+
+  /// The locale for which the values of this class's localized resources
+  /// have been translated.
+  Locale get locale => const Locale('en', 'US');
+
+  /// The reading direction for text in this locale.
+  TextDirection get textDirection => TextDirection.ltr;
+
+  /// The `WidgetsLocalizations` from the closest [Localizations] instance
+  /// that encloses the given context.
+  ///
+  /// This method is just a convenient shorthand for:
+  /// `Localizations.of<WidgetsLocalizations>(context, WidgetsLocalizations)`.
+  ///
+  /// References to the localized resources defined by this class are typically
+  /// written in terms of this method. For example:
+  ///
+  /// ```dart
+  /// textDirection: WidgetsLocalizations.of(context).textDirection,
+  /// ```
+  static WidgetsLocalizations of(BuildContext context) {
+    return Localizations.of<WidgetsLocalizations>(context, WidgetsLocalizations);
+  }
 }
 
 class _LocalizationsScope extends InheritedWidget {
@@ -158,7 +200,7 @@ class _LocalizationsScope extends InheritedWidget {
 ///
 /// This class is effectively an [InheritedWidget]. If it's rebuilt with
 /// a new `locale` or a different list of delegates or any of its
-/// delegates' [LocalizationDelegate.shouldReload()] methods returns true,
+/// delegates' [LocalizationsDelegate.shouldReload()] methods returns true,
 /// then widgets that have created a dependency by calling
 /// `Localizations.of(context)` will be rebuilt after the resources
 /// for the new locale have been loaded.
@@ -199,21 +241,25 @@ class _LocalizationsScope extends InheritedWidget {
 /// One could choose another approach for loading localized resources and looking them up while
 /// still conforming to the structure of this example.
 class Localizations extends StatefulWidget {
+  /// Create a widget from which ambient localizations (translated strings)
+  /// can be obtained.
   Localizations({
     Key key,
     @required this.locale,
-    this.delegates,
-    this.child
-  }) : super(key: key) {
-    assert(locale != null);
+    @required this.delegates,
+    this.child,
+  }) : assert(locale != null),
+       assert(delegates != null),
+       super(key: key) {
+    assert(delegates.any((LocalizationsDelegate<dynamic> delegate) => delegate is LocalizationsDelegate<WidgetsLocalizations>));
   }
 
   /// The resources returned by [Localizations.of] will be specific to this locale.
   final Locale locale;
 
   /// This list collectively defines the localized resources objects that can
-  /// be retrieved with [ Localizations.of].
-  final Iterable<LocalizationsDelegate<dynamic>> delegates;
+  /// be retrieved with [Localizations.of].
+  final List<LocalizationsDelegate<dynamic>> delegates;
 
   /// The widget below this widget in the tree.
   final Widget child;
@@ -247,6 +293,13 @@ class Localizations extends StatefulWidget {
 
   @override
   _LocalizationsState createState() => new _LocalizationsState();
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder description) {
+    super.debugFillProperties(description);
+    description.add(new DiagnosticsProperty<Locale>('locale', locale));
+    description.add(new IterableProperty<LocalizationsDelegate<dynamic>>('delegates', delegates));
+  }
 }
 
 class _LocalizationsState extends State<Localizations> {
@@ -329,18 +382,29 @@ class _LocalizationsState extends State<Localizations> {
 
   T resourcesFor<T>(Type type) {
     assert(type != null);
-    final dynamic resources = _typeToResources[type];
+    final T resources = _typeToResources[type];
     assert(resources.runtimeType == type);
     return resources;
   }
 
+  TextDirection get _textDirection {
+    final WidgetsLocalizations resources = _typeToResources[WidgetsLocalizations];
+    assert(resources != null);
+    return resources.textDirection;
+  }
+
   @override
   Widget build(BuildContext context) {
+    if (_locale == null)
+      return new Container();
     return new _LocalizationsScope(
       key: _localizedResourcesScopeKey,
-      locale: widget.locale,
+      locale: _locale,
       localizationsState: this,
-      child: _locale != null ? widget.child : new Container(),
+      child: new Directionality(
+        textDirection: _textDirection,
+        child: widget.child,
+      ),
     );
   }
 }

packages/flutter/lib/src/widgets/scroll_controller.dart

@@ -264,7 +264,7 @@ class ScrollController extends ChangeNotifier {
       description.add('no clients');
     } else if (_positions.length == 1) {
       // Don't actually list the client itself, since its toString may refer to us.
-      description.add('one client, offset ${offset.toStringAsFixed(1)}');
+      description.add('one client, offset ${offset?.toStringAsFixed(1)}');
     } else {
       description.add('${_positions.length} clients');
     }

packages/flutter/test/cupertino/bottom_tab_bar_test.dart

@@ -7,10 +7,19 @@ import 'package:flutter_test/flutter_test.dart';
 
 import '../services/mocks_for_image_cache.dart';
 
+Future<Null> pumpWidgetWithBoilerplate(WidgetTester tester, Widget widget) async {
+  await tester.pumpWidget(
+    new Directionality(
+      textDirection: TextDirection.ltr,
+      child: widget,
+    ),
+  );
+}
+
 void main() {
   testWidgets('Need at least 2 tabs', (WidgetTester tester) async {
     try {
-      await tester.pumpWidget(new CupertinoTabBar(
+      await pumpWidgetWithBoilerplate(tester, new CupertinoTabBar(
         items: <BottomNavigationBarItem>[
           const BottomNavigationBarItem(
             icon: const ImageIcon(const TestImageProvider(24, 24)),
@@ -19,13 +28,14 @@ void main() {
         ],
       ));
       fail('Should not be possible to create a tab bar with just one item');
-    } on AssertionError {
+    } on AssertionError catch (e) {
+      expect(e.toString(), contains('items.length'));
       // Exception expected.
     }
   });
 
   testWidgets('Active and inactive colors', (WidgetTester tester) async {
-    await tester.pumpWidget(new CupertinoTabBar(
+    await pumpWidgetWithBoilerplate(tester, new CupertinoTabBar(
       items: <BottomNavigationBarItem>[
         const BottomNavigationBarItem(
           icon: const ImageIcon(const TestImageProvider(24, 24)),
@@ -55,7 +65,7 @@ void main() {
   });
 
   testWidgets('Opaque background does not add blur effects', (WidgetTester tester) async {
-    await tester.pumpWidget(new CupertinoTabBar(
+    await pumpWidgetWithBoilerplate(tester, new CupertinoTabBar(
       items: <BottomNavigationBarItem>[
         const BottomNavigationBarItem(
           icon: const ImageIcon(const TestImageProvider(24, 24)),
@@ -70,7 +80,7 @@ void main() {
 
     expect(find.byType(BackdropFilter), findsOneWidget);
 
-    await tester.pumpWidget(new CupertinoTabBar(
+    await pumpWidgetWithBoilerplate(tester, new CupertinoTabBar(
       items: <BottomNavigationBarItem>[
         const BottomNavigationBarItem(
           icon: const ImageIcon(const TestImageProvider(24, 24)),
@@ -90,7 +100,7 @@ void main() {
   testWidgets('Tap callback', (WidgetTester tester) async {
     int callbackTab;
 
-    await tester.pumpWidget(new CupertinoTabBar(
+      await pumpWidgetWithBoilerplate(tester, new CupertinoTabBar(
       items: <BottomNavigationBarItem>[
         const BottomNavigationBarItem(
           icon: const ImageIcon(const TestImageProvider(24, 24)),

packages/flutter/test/material/about_test.dart

@@ -67,7 +67,10 @@ void main() {
 
   testWidgets('About box logic defaults to executable name for app name', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Material(child: const AboutListTile()),
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Material(child: const AboutListTile()),
+      ),
     );
     expect(find.text('About flutter_tester'), findsOneWidget);
   });

packages/flutter/test/material/app_bar_test.dart

@@ -8,31 +8,34 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 Widget buildSliverAppBarApp({ bool floating, bool pinned, double expandedHeight, bool snap: false }) {
-  return new MediaQuery(
-    data: const MediaQueryData(),
-    child: new Scaffold(
-      body: new DefaultTabController(
-        length: 3,
-        child: new CustomScrollView(
-          primary: true,
-          slivers: <Widget>[
-            new SliverAppBar(
-              title: const Text('AppBar Title'),
-              floating: floating,
-              pinned: pinned,
-              expandedHeight: expandedHeight,
-              snap: snap,
-              bottom: new TabBar(
-                tabs: <String>['A','B','C'].map((String t) => new Tab(text: 'TAB $t')).toList(),
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new MediaQuery(
+      data: const MediaQueryData(),
+      child: new Scaffold(
+        body: new DefaultTabController(
+          length: 3,
+          child: new CustomScrollView(
+            primary: true,
+            slivers: <Widget>[
+              new SliverAppBar(
+                title: const Text('AppBar Title'),
+                floating: floating,
+                pinned: pinned,
+                expandedHeight: expandedHeight,
+                snap: snap,
+                bottom: new TabBar(
+                  tabs: <String>['A','B','C'].map((String t) => new Tab(text: 'TAB $t')).toList(),
+                ),
               ),
-            ),
-            new SliverToBoxAdapter(
-              child: new Container(
-                height: 1200.0,
-                color: Colors.orange[400],
+              new SliverToBoxAdapter(
+                child: new Container(
+                  height: 1200.0,
+                  color: Colors.orange[400],
+                ),
               ),
-            ),
-          ],
+            ],
+          ),
         ),
       ),
     ),
@@ -699,11 +702,14 @@ void main() {
     const MediaQueryData topPadding100 = const MediaQueryData(padding: const EdgeInsets.only(top: 100.0));
 
     await tester.pumpWidget(
-      new MediaQuery(
-        data: topPadding100,
-        child: new Scaffold(
-          primary: false,
-          appBar: new AppBar(),
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new MediaQuery(
+          data: topPadding100,
+          child: new Scaffold(
+            primary: false,
+            appBar: new AppBar(),
+          ),
         ),
       ),
     );
@@ -711,11 +717,14 @@ void main() {
     expect(appBarHeight(tester), kToolbarHeight);
 
     await tester.pumpWidget(
-      new MediaQuery(
-        data: topPadding100,
-        child: new Scaffold(
-          primary: true,
-          appBar: new AppBar(title: const Text('title'))
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new MediaQuery(
+          data: topPadding100,
+          child: new Scaffold(
+            primary: true,
+            appBar: new AppBar(title: const Text('title'))
+          ),
         ),
       ),
     );
@@ -724,14 +733,17 @@ void main() {
     expect(appBarHeight(tester), kToolbarHeight + 100.0);
 
     await tester.pumpWidget(
-      new MediaQuery(
-        data: topPadding100,
-        child: new Scaffold(
-          primary: false,
-          appBar: new AppBar(
-            bottom: new PreferredSize(
-              preferredSize: const Size.fromHeight(200.0),
-              child: new Container(),
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new MediaQuery(
+          data: topPadding100,
+          child: new Scaffold(
+            primary: false,
+            appBar: new AppBar(
+              bottom: new PreferredSize(
+                preferredSize: const Size.fromHeight(200.0),
+                child: new Container(),
+              ),
             ),
           ),
         ),
@@ -741,14 +753,17 @@ void main() {
     expect(appBarHeight(tester), kToolbarHeight + 200.0);
 
     await tester.pumpWidget(
-      new MediaQuery(
-        data: topPadding100,
-        child: new Scaffold(
-          primary: true,
-          appBar: new AppBar(
-            bottom: new PreferredSize(
-              preferredSize: const Size.fromHeight(200.0),
-              child: new Container(),
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new MediaQuery(
+          data: topPadding100,
+          child: new Scaffold(
+            primary: true,
+            appBar: new AppBar(
+              bottom: new PreferredSize(
+                preferredSize: const Size.fromHeight(200.0),
+                child: new Container(),
+              ),
             ),
           ),
         ),
@@ -758,11 +773,14 @@ void main() {
     expect(appBarHeight(tester), kToolbarHeight + 100.0 + 200.0);
 
     await tester.pumpWidget(
-      new MediaQuery(
-        data: topPadding100,
-        child: new AppBar(
-          primary: false,
-          title: const Text('title'),
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new MediaQuery(
+          data: topPadding100,
+          child: new AppBar(
+            primary: false,
+            title: const Text('title'),
+          ),
         ),
       ),
     );

packages/flutter/test/material/button_bar_test.dart

@@ -6,7 +6,12 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  testWidgets('ButtonBar default control', (WidgetTester tester) async {
-    await tester.pumpWidget(const Center(child: const ButtonBar()));
+  testWidgets('ButtonBar default control smoketest', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: const ButtonBar(),
+      ),
+    );
   });
 }

packages/flutter/test/material/chip_test.dart

@@ -107,29 +107,31 @@ void main() {
     feedback.dispose();
   });
 
-  testWidgets(
-      'Chip does not constrain size of label widget if it does not exceed '
-      'the available space', (WidgetTester tester) async {
+  testWidgets('Chip does not constrain size of label widget if it does not exceed '
+              'the available space', (WidgetTester tester) async {
     const double labelWidth = 50.0;
     const double labelHeight = 30.0;
     final Key labelKey = new UniqueKey();
 
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
-          child: new Container(
-            width: 500.0,
-            height: 500.0,
-            child: new Column(
-              children: <Widget>[
-                new Chip(
-                  label: new Container(
-                    key: labelKey,
-                    width: labelWidth,
-                    height: labelHeight,
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Material(
+          child: new Center(
+            child: new Container(
+              width: 500.0,
+              height: 500.0,
+              child: new Column(
+                children: <Widget>[
+                  new Chip(
+                    label: new Container(
+                      key: labelKey,
+                      width: labelWidth,
+                      height: labelHeight,
+                    ),
                   ),
-                ),
-              ],
+                ],
+              ),
             ),
           ),
         ),
@@ -141,15 +143,13 @@ void main() {
     expect(labelSize.height, labelHeight);
   });
 
-  testWidgets(
-      'Chip constrains the size of the label widget when it exceeds the '
-      'available space', (WidgetTester tester) async {
+  testWidgets('Chip constrains the size of the label widget when it exceeds the '
+              'available space', (WidgetTester tester) async {
     await _testConstrainedLabel(tester);
   });
 
-  testWidgets(
-      'Chip constrains the size of the label widget when it exceeds the '
-      'available space and the avatar is present', (WidgetTester tester) async {
+  testWidgets('Chip constrains the size of the label widget when it exceeds the '
+              'available space and the avatar is present', (WidgetTester tester) async {
     await _testConstrainedLabel(
       tester,
       avatar: const CircleAvatar(
@@ -158,20 +158,16 @@ void main() {
     );
   });
 
-  testWidgets(
-      'Chip constrains the size of the label widget when it exceeds the '
-      'available space and the delete icon is present',
-      (WidgetTester tester) async {
+  testWidgets('Chip constrains the size of the label widget when it exceeds the '
+              'available space and the delete icon is present', (WidgetTester tester) async {
     await _testConstrainedLabel(
       tester,
       onDeleted: () {},
     );
   });
 
-  testWidgets(
-      'Chip constrains the size of the label widget when it exceeds the '
-      'available space and both avatar and delete icons are present',
-      (WidgetTester tester) async {
+  testWidgets('Chip constrains the size of the label widget when it exceeds the '
+              'available space and both avatar and delete icons are present', (WidgetTester tester) async {
     await _testConstrainedLabel(
       tester,
       avatar: const CircleAvatar(
@@ -223,4 +219,104 @@ void main() {
     expect(tester.getSize(find.byType(Text)), const Size(40.0, 10.0));
     expect(tester.getSize(find.byType(Chip)), const Size(800.0, 32.0));
   });
+  testWidgets('Chip supports RTL', (WidgetTester tester) async {
+    final Widget test = new Overlay(
+      initialEntries: <OverlayEntry>[
+        new OverlayEntry(
+          builder: (BuildContext context) {
+            return new Material(
+              child: new Center(
+                child: new Chip(
+                  onDeleted: () { },
+                  label: new Text('ABC'),
+                ),
+              ),
+            );
+          },
+        ),
+      ],
+    );
+
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.rtl,
+        child: test,
+      ),
+    );
+    expect(tester.getCenter(find.text('ABC')).dx, greaterThan(tester.getCenter(find.byType(Icon)).dx));
+
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: test,
+      ),
+    );
+    expect(tester.getCenter(find.text('ABC')).dx, lessThan(tester.getCenter(find.byType(Icon)).dx));
+  });
+
+  testWidgets('Chip padding - LTR', (WidgetTester tester) async {
+    final GlobalKey keyA = new GlobalKey();
+    final GlobalKey keyB = new GlobalKey();
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
+          initialEntries: <OverlayEntry>[
+            new OverlayEntry(
+              builder: (BuildContext context) {
+                return new Material(
+                  child: new Center(
+                    child: new Chip(
+                      avatar: new Placeholder(key: keyA),
+                      label: new Placeholder(key: keyB),
+                      onDeleted: () { },
+                    ),
+                  ),
+                );
+              },
+            ),
+          ],
+        ),
+      ),
+    );
+    expect(tester.getTopLeft(find.byKey(keyA)), const Offset(0.0, 284.0));
+    expect(tester.getBottomRight(find.byKey(keyA)), const Offset(32.0, 316.0));
+    expect(tester.getTopLeft(find.byKey(keyB)), const Offset(40.0, 284.0));
+    expect(tester.getBottomRight(find.byKey(keyB)), const Offset(774.0, 316.0));
+    expect(tester.getTopLeft(find.byType(Icon)), const Offset(778.0, 291.0));
+    expect(tester.getBottomRight(find.byType(Icon)), const Offset(796.0, 309.0));
+  });
+
+  testWidgets('Chip padding - RTL', (WidgetTester tester) async {
+    final GlobalKey keyA = new GlobalKey();
+    final GlobalKey keyB = new GlobalKey();
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.rtl,
+        child: new Overlay(
+          initialEntries: <OverlayEntry>[
+            new OverlayEntry(
+              builder: (BuildContext context) {
+                return new Material(
+                  child: new Center(
+                    child: new Chip(
+                      avatar: new Placeholder(key: keyA),
+                      label: new Placeholder(key: keyB),
+                      onDeleted: () { },
+                    ),
+                  ),
+                );
+              },
+            ),
+          ],
+        ),
+      ),
+    );
+    expect(tester.getTopRight(find.byKey(keyA)), const Offset(800.0 - 0.0, 284.0));
+    expect(tester.getBottomLeft(find.byKey(keyA)), const Offset(800.0 - 32.0, 316.0));
+    expect(tester.getTopRight(find.byKey(keyB)), const Offset(800.0 - 40.0, 284.0));
+    expect(tester.getBottomLeft(find.byKey(keyB)), const Offset(800.0 - 774.0, 316.0));
+    expect(tester.getTopRight(find.byType(Icon)), const Offset(800.0 - 778.0, 291.0));
+    expect(tester.getBottomLeft(find.byType(Icon)), const Offset(800.0 - 796.0, 309.0));
+  });
 }

packages/flutter/test/material/control_list_tile_test.dart

@@ -10,10 +10,17 @@ import 'package:flutter/rendering.dart';
 
 import '../widgets/semantics_tester.dart';
 
+Widget wrap({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Material(child: child),
+  );
+}
+
 void main() {
   testWidgets('CheckboxListTile control test', (WidgetTester tester) async {
     final List<dynamic> log = <dynamic>[];
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(wrap(
       child: new CheckboxListTile(
         value: true,
         onChanged: (bool value) { log.add(value); },
@@ -28,7 +35,7 @@ void main() {
 
   testWidgets('RadioListTile control test', (WidgetTester tester) async {
     final List<dynamic> log = <dynamic>[];
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(wrap(
       child: new RadioListTile<bool>(
         value: true,
         groupValue: false,
@@ -44,7 +51,7 @@ void main() {
 
   testWidgets('SwitchListTile control test', (WidgetTester tester) async {
     final List<dynamic> log = <dynamic>[];
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(wrap(
       child: new SwitchListTile(
         value: true,
         onChanged: (bool value) { log.add(value); },
@@ -59,7 +66,7 @@ void main() {
 
   testWidgets('SwitchListTile control test', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(wrap(
       child: new Column(
         children: <Widget>[
           new SwitchListTile(

packages/flutter/test/material/expansion_panel_test.dart

@@ -11,22 +11,24 @@ void main() {
     bool isExpanded;
 
     await tester.pumpWidget(
-      new SingleChildScrollView(
-        child: new ExpansionPanelList(
-          expansionCallback: (int _index, bool _isExpanded) {
-            index = _index;
-            isExpanded = _isExpanded;
-          },
-          children: <ExpansionPanel>[
-            new ExpansionPanel(
-              headerBuilder: (BuildContext context, bool isExpanded) {
-                return new Text(isExpanded ? 'B' : 'A');
-              },
-              body: const SizedBox(height: 100.0)
-            )
-          ]
-        )
-      )
+      new MaterialApp(
+        home: new SingleChildScrollView(
+          child: new ExpansionPanelList(
+            expansionCallback: (int _index, bool _isExpanded) {
+              index = _index;
+              isExpanded = _isExpanded;
+            },
+            children: <ExpansionPanel>[
+              new ExpansionPanel(
+                headerBuilder: (BuildContext context, bool isExpanded) {
+                  return new Text(isExpanded ? 'B' : 'A');
+                },
+                body: const SizedBox(height: 100.0),
+              ),
+            ],
+          ),
+        ),
+      ),
     );
 
     expect(find.text('A'), findsOneWidget);
@@ -42,28 +44,28 @@ void main() {
 
     // now expand the child panel
     await tester.pumpWidget(
-      new SingleChildScrollView(
-        child: new ExpansionPanelList(
-          expansionCallback: (int _index, bool _isExpanded) {
-            index = _index;
-            isExpanded = _isExpanded;
-          },
-          children: <ExpansionPanel>[
-            new ExpansionPanel(
-              headerBuilder: (BuildContext context, bool isExpanded) {
-                return new Text(isExpanded ? 'B' : 'A');
-              },
-              body: const SizedBox(height: 100.0),
-              isExpanded: true // this is the addition
-            )
-          ]
-        )
-      )
+      new MaterialApp(
+        home: new SingleChildScrollView(
+          child: new ExpansionPanelList(
+            expansionCallback: (int _index, bool _isExpanded) {
+              index = _index;
+              isExpanded = _isExpanded;
+            },
+            children: <ExpansionPanel>[
+              new ExpansionPanel(
+                headerBuilder: (BuildContext context, bool isExpanded) {
+                  return new Text(isExpanded ? 'B' : 'A');
+                },
+                body: const SizedBox(height: 100.0),
+                isExpanded: true, // this is the addition
+              ),
+            ],
+          ),
+        ),
+      ),
     );
-
     await tester.pump(const Duration(milliseconds: 200));
 
-
     expect(find.text('A'), findsNothing);
     expect(find.text('B'), findsOneWidget);
     box = tester.renderObject(find.byType(ExpansionPanelList));

packages/flutter/test/material/grid_title_test.dart

@@ -10,23 +10,25 @@ void main() {
     final Key headerKey = new UniqueKey();
     final Key footerKey = new UniqueKey();
 
-    await tester.pumpWidget(new GridTile(
-      header: new GridTileBar(
-        key: headerKey,
-        leading: const Icon(Icons.thumb_up),
-        title: const Text('Header'),
-        subtitle: const Text('Subtitle'),
-        trailing: const Icon(Icons.thumb_up),
-      ),
-      child: new DecoratedBox(
-        decoration: new BoxDecoration(
-          color: Colors.green[500],
+    await tester.pumpWidget(new MaterialApp(
+      home: new GridTile(
+        header: new GridTileBar(
+          key: headerKey,
+          leading: const Icon(Icons.thumb_up),
+          title: const Text('Header'),
+          subtitle: const Text('Subtitle'),
+          trailing: const Icon(Icons.thumb_up),
+        ),
+        child: new DecoratedBox(
+          decoration: new BoxDecoration(
+            color: Colors.green[500],
+          ),
+        ),
+        footer: new GridTileBar(
+          key: footerKey,
+          title: const Text('Footer'),
+          backgroundColor: Colors.black38,
         ),
-      ),
-      footer: new GridTileBar(
-        key: footerKey,
-        title: const Text('Footer'),
-        backgroundColor: Colors.black38,
       ),
     ));
 

packages/flutter/test/material/icon_button_test.dart

@@ -98,15 +98,18 @@ void main() {
     'test default icon buttons can be stretched if specified',
     (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Row(
-          crossAxisAlignment: CrossAxisAlignment.stretch,
-          children: <Widget> [
-            new IconButton(
-              onPressed: mockOnPressedFunction,
-              icon: const Icon(Icons.ac_unit),
-            ),
-          ],
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Material(
+          child: new Row(
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: <Widget> [
+              new IconButton(
+                onPressed: mockOnPressedFunction,
+                icon: const Icon(Icons.ac_unit),
+              ),
+            ],
+          ),
         ),
       ),
     );

packages/flutter/test/material/input_decorator_test.dart

@@ -9,37 +9,43 @@ void main() {
   testWidgets('InputDecorator always expands horizontally', (WidgetTester tester) async {
     final Key key = new UniqueKey();
 
-    await tester.pumpWidget(new Material(
-      child: new Center(
-        child: new InputDecorator(
-          decoration: const InputDecoration(),
-          child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
+    await tester.pumpWidget(new MaterialApp(
+      home: new Material(
+        child: new Center(
+          child: new InputDecorator(
+            decoration: const InputDecoration(),
+            child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
+          ),
         ),
       ),
     ));
 
     expect(tester.element(find.byKey(key)).size, equals(const Size(800.0, 60.0)));
 
-    await tester.pumpWidget(new Material(
-      child: new Center(
-        child: new InputDecorator(
-          decoration: const InputDecoration(
-            icon: const Icon(Icons.add_shopping_cart),
+    await tester.pumpWidget(new MaterialApp(
+      home: new Material(
+        child: new Center(
+          child: new InputDecorator(
+            decoration: const InputDecoration(
+              icon: const Icon(Icons.add_shopping_cart),
+            ),
+            child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
           ),
-          child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
         ),
       ),
     ));
 
     expect(tester.element(find.byKey(key)).size, equals(const Size(752.0, 60.0)));
 
-    await tester.pumpWidget(new Material(
-      child: new Center(
-        child: new InputDecorator(
-          decoration: const InputDecoration.collapsed(
-            hintText: 'Hint text',
+    await tester.pumpWidget(new MaterialApp(
+      home: new Material(
+        child: new Center(
+          child: new InputDecorator(
+            decoration: const InputDecoration.collapsed(
+              hintText: 'Hint text',
+            ),
+            child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
           ),
-          child: new Container(key: key, width: 50.0, height: 60.0, color: Colors.blue),
         ),
       ),
     ));

packages/flutter/test/material/page_selector_test.dart

@@ -9,32 +9,35 @@ const Color kSelectedColor = const Color(0xFF00FF00);
 const Color kUnselectedColor = Colors.transparent;
 
 Widget buildFrame(TabController tabController, { Color color, Color selectedColor, double indicatorSize: 12.0 }) {
-  return new Theme(
-    data: new ThemeData(accentColor: kSelectedColor),
-    child: new SizedBox.expand(
-      child: new Center(
-        child: new SizedBox(
-          width: 400.0,
-          height: 400.0,
-          child: new Column(
-            children: <Widget>[
-              new TabPageSelector(
-                controller: tabController,
-                color: color,
-                selectedColor: selectedColor,
-                indicatorSize: indicatorSize,
-              ),
-              new Flexible(
-                child: new TabBarView(
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Theme(
+      data: new ThemeData(accentColor: kSelectedColor),
+      child: new SizedBox.expand(
+        child: new Center(
+          child: new SizedBox(
+            width: 400.0,
+            height: 400.0,
+            child: new Column(
+              children: <Widget>[
+                new TabPageSelector(
                   controller: tabController,
-                  children: <Widget>[
-                    const Center(child: const Text('0')),
-                    const Center(child: const Text('1')),
-                    const Center(child: const Text('2')),
-                  ],
+                  color: color,
+                  selectedColor: selectedColor,
+                  indicatorSize: indicatorSize,
                 ),
-              ),
-            ],
+                new Flexible(
+                  child: new TabBarView(
+                    controller: tabController,
+                    children: <Widget>[
+                      const Center(child: const Text('0')),
+                      const Center(child: const Text('1')),
+                      const Center(child: const Text('2')),
+                    ],
+                  ),
+                ),
+              ],
+            ),
           ),
         ),
       ),

packages/flutter/test/material/tabs_test.dart

@@ -14,6 +14,15 @@ import '../rendering/mock_canvas.dart';
 import '../rendering/recording_canvas.dart';
 import '../widgets/semantics_tester.dart';
 
+Widget boilerplate({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Material(
+      child: child,
+    ),
+  );
+}
+
 class StateMarker extends StatefulWidget {
   const StateMarker({ Key key, this.child }) : super(key: key);
 
@@ -41,7 +50,7 @@ Widget buildFrame({
     bool isScrollable: false,
     Color indicatorColor,
   }) {
-  return new Material(
+  return boilerplate(
     child: new DefaultTabController(
       initialIndex: tabs.indexOf(value),
       length: tabs.length,
@@ -253,7 +262,7 @@ void main() {
     String value = tabs[0];
 
     Widget builder() {
-      return new Material(
+      return boilerplate(
         child: new DefaultTabController(
           initialIndex: tabs.indexOf(value),
           length: tabs.length,
@@ -633,7 +642,7 @@ void main() {
     Color secondColor;
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new TabBar(
           controller: controller,
           labelColor: Colors.green[500],
@@ -667,7 +676,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new TabBarView(
           controller: controller,
           children: <Widget>[ const Text('First'), const Text('Second') ],
@@ -765,7 +774,7 @@ void main() {
     );
 
     Widget buildFrame() {
-      return new Material(
+      return boilerplate(
         child: new TabBar(
           key: new UniqueKey(),
           controller: controller,
@@ -893,7 +902,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new TabBar(
           isScrollable: true,
           controller: controller,
@@ -927,7 +936,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new Column(
           children: <Widget>[
             new TabBar(
@@ -985,7 +994,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new Semantics(
           container: true,
           child: new TabBar(
@@ -1034,7 +1043,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new Column(
           children: <Widget>[
             new TabBar(
@@ -1074,7 +1083,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new Column(
           children: <Widget>[
             new TabBar(
@@ -1129,7 +1138,7 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Material(
+      boilerplate(
         child: new Column(
           children: <Widget>[
             new TabBar(

packages/flutter/test/painting/box_painter_test.dart

@@ -167,7 +167,7 @@ void main() {
         ],
       ).toString(),
       equals(
-        'LinearGradient(FractionalOffset(0.0, 0.0), FractionalOffset(0.0, 1.0), [Color(0x33333333), Color(0x66666666)], null, TileMode.clamp)',
+        'LinearGradient(FractionalOffset.topLeft, FractionalOffset.bottomLeft, [Color(0x33333333), Color(0x66666666)], null, TileMode.clamp)',
       ),
     );
   });

packages/flutter/test/rendering/limited_box_test.dart

@@ -36,7 +36,7 @@ void main() {
         ' │ parentData: <none>\n'
         ' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
         ' │ size: Size(800.0, 600.0)\n'
-        ' │ alignment: FractionalOffset(0.5, 0.5)\n'
+        ' │ alignment: FractionalOffset.center\n'
         ' │ minWidth: 0.0\n'
         ' │ maxWidth: Infinity\n'
         ' │ minHeight: 0.0\n'
@@ -122,7 +122,7 @@ void main() {
         ' │ parentData: <none>\n'
         ' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
         ' │ size: Size(800.0, 600.0)\n'
-        ' │ alignment: FractionalOffset(0.5, 0.5)\n'
+        ' │ alignment: FractionalOffset.center\n'
         ' │ minWidth: 10.0\n'
         ' │ maxWidth: 500.0\n'
         ' │ minHeight: 0.0\n'
@@ -158,7 +158,7 @@ void main() {
         ' │ parentData: <none>\n'
         ' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
         ' │ size: Size(800.0, 600.0)\n'
-        ' │ alignment: FractionalOffset(0.5, 0.5)\n'
+        ' │ alignment: FractionalOffset.center\n'
         ' │ minWidth: 10.0\n'
         ' │ maxWidth: use parent maxWidth constraint\n'
         ' │ minHeight: use parent minHeight constraint\n'

packages/flutter/test/rendering/mutations_test.dart

@@ -36,7 +36,7 @@ void main() {
     RenderBox child1, child2;
     bool movedChild1 = false;
     bool movedChild2 = false;
-    final RenderFlex block = new RenderFlex();
+    final RenderFlex block = new RenderFlex(textDirection: TextDirection.ltr);
     block.add(child1 = new RenderLayoutTestBox(() { movedChild1 = true; }));
     block.add(child2 = new RenderLayoutTestBox(() { movedChild2 = true; }));
 

packages/flutter/test/widgets/clamp_overscrolls_test.dart

@@ -19,6 +19,7 @@ Widget buildFrame(ScrollPhysics physics) {
       height: 650.0,
       child: new Column(
         crossAxisAlignment: CrossAxisAlignment.start,
+        textDirection: TextDirection.ltr,
         children: <Widget>[
           const SizedBox(height: 100.0, child: const Text('top')),
           new Expanded(child: new Container()),

packages/flutter/test/widgets/container_test.dart

@@ -59,7 +59,8 @@ void main() {
         ' │ parentData: offset=Offset(0.0, 0.0) (can use size)\n'
         ' │ constraints: BoxConstraints(0.0<=w<=800.0, 0.0<=h<=600.0)\n'
         ' │ size: Size(63.0, 88.0)\n'
-        ' │ padding: EdgeInsets(5.0, 5.0, 5.0, 5.0)\n'
+        ' │ padding: EdgeInsets.all(5.0)\n'
+        ' │ textDirection: null\n'
         ' │\n'
         ' └─child: RenderConstrainedBox#00000 relayoutBoundary=up2\n'
         '   │ creator: ConstrainedBox ← Padding ← Container ← Align ← [root]\n'
@@ -98,7 +99,8 @@ void main() {
         '         │ parentData: <none> (can use size)\n'
         '         │ constraints: BoxConstraints(w=53.0, h=78.0)\n'
         '         │ size: Size(53.0, 78.0)\n'
-        '         │ padding: EdgeInsets(7.0, 7.0, 7.0, 7.0)\n'
+        '         │ padding: EdgeInsets.all(7.0)\n'
+        '         │ textDirection: null\n'
         '         │\n'
         '         └─child: RenderPositionedBox#00000\n'
         '           │ creator: Align ← Padding ← DecoratedBox ← DecoratedBox ←\n'
@@ -106,7 +108,7 @@ void main() {
         '           │ parentData: offset=Offset(7.0, 7.0) (can use size)\n'
         '           │ constraints: BoxConstraints(w=39.0, h=64.0)\n'
         '           │ size: Size(39.0, 64.0)\n'
-        '           │ alignment: FractionalOffset(1.0, 1.0)\n'
+        '           │ alignment: FractionalOffset.bottomRight\n'
         '           │ widthFactor: expand\n'
         '           │ heightFactor: expand\n'
         '           │\n'

packages/flutter/test/widgets/flex_test.dart

@@ -47,6 +47,7 @@ void main() {
   testWidgets('Flexible defaults to loose', (WidgetTester tester) async {
     await tester.pumpWidget(
       new Row(
+        textDirection: TextDirection.ltr,
         children: <Widget>[
           const Flexible(child: const SizedBox(width: 100.0, height: 200.0)),
         ],
@@ -60,6 +61,7 @@ void main() {
   testWidgets('Can pass null for flex', (WidgetTester tester) async {
     await tester.pumpWidget(
       new Row(
+        textDirection: TextDirection.ltr,
         children: <Widget>[
           const Expanded(flex: null, child: const Text('one')),
           const Flexible(flex: null, child: const Text('two')),

packages/flutter/test/widgets/focus_test.dart

@@ -145,6 +145,7 @@ void main() {
         node: parentFocusScope,
         autofocus: true,
         child: new Row(
+          textDirection: TextDirection.ltr,
           children: <Widget>[
             const TestFocusable(
               no: 'a',
@@ -193,6 +194,7 @@ void main() {
       new FocusScope(
         node: parentFocusScope,
         child: new Row(
+          textDirection: TextDirection.ltr,
           children: <Widget>[
             const TestFocusable(
               no: 'a',
@@ -218,6 +220,7 @@ void main() {
       new FocusScope(
         node: parentFocusScope,
         child: new Row(
+          textDirection: TextDirection.ltr,
           children: <Widget>[
             const TestFocusable(
               no: 'a',

packages/flutter/test/widgets/framework_test.dart

@@ -486,7 +486,7 @@ void main() {
     expect(
       element.toStringDeep(),
       equalsIgnoringHashCodes(
-        'Column-[GlobalKey#00000](renderObject: RenderFlex#00000)\n'
+        'Column-[GlobalKey#00000](direction: vertical, mainAxisAlignment: start, crossAxisAlignment: center, renderObject: RenderFlex#00000)\n'
         '├Container\n'
         '│└LimitedBox(maxWidth: 0.0, maxHeight: 0.0, renderObject: RenderLimitedBox#00000 relayoutBoundary=up1)\n'
         '│ └ConstrainedBox(BoxConstraints(biggest), renderObject: RenderConstrainedBox#00000 relayoutBoundary=up2)\n'

packages/flutter/test/widgets/global_keys_duplicated_test.dart

@@ -24,10 +24,13 @@ void main() {
   });
 
   testWidgets('GlobalKey children of two nodes', (WidgetTester tester) async {
-    await tester.pumpWidget(new Row(children: <Widget>[
-      new Container(child: new Container(key: const GlobalObjectKey(0))),
-      new Container(child: new Container(key: const GlobalObjectKey(0))),
-    ]));
+    await tester.pumpWidget(new Row(
+      textDirection: TextDirection.ltr,
+      children: <Widget>[
+        new Container(child: new Container(key: const GlobalObjectKey(0))),
+        new Container(child: new Container(key: const GlobalObjectKey(0))),
+      ],
+    ));
     final dynamic error = tester.takeException();
     expect(error, isFlutterError);
     expect(error.toString(), startsWith('Multiple widgets used the same GlobalKey.\n'));
@@ -38,10 +41,13 @@ void main() {
   });
 
   testWidgets('GlobalKey children of two different nodes', (WidgetTester tester) async {
-    await tester.pumpWidget(new Row(children: <Widget>[
-      new Container(child: new Container(key: const GlobalObjectKey(0))),
-      new Container(key: const Key('x'), child: new Container(key: const GlobalObjectKey(0))),
-    ]));
+    await tester.pumpWidget(new Row(
+      textDirection: TextDirection.ltr,
+      children: <Widget>[
+        new Container(child: new Container(key: const GlobalObjectKey(0))),
+        new Container(key: const Key('x'), child: new Container(key: const GlobalObjectKey(0))),
+      ],
+    ));
     final dynamic error = tester.takeException();
     expect(error, isFlutterError);
     expect(error.toString(), startsWith('Multiple widgets used the same GlobalKey.\n'));
@@ -55,17 +61,20 @@ void main() {
   testWidgets('GlobalKey children of two nodes', (WidgetTester tester) async {
     StateSetter nestedSetState;
     bool flag = false;
-    await tester.pumpWidget(new Row(children: <Widget>[
-      new Container(child: new Container(key: const GlobalObjectKey(0))),
-      new Container(child: new StatefulBuilder(
-        builder: (BuildContext context, StateSetter setState) {
-          nestedSetState = setState;
-          if (flag)
-            return new Container(key: const GlobalObjectKey(0));
-          return new Container();
-        },
-      )),
-    ]));
+    await tester.pumpWidget(new Row(
+      textDirection: TextDirection.ltr,
+      children: <Widget>[
+        new Container(child: new Container(key: const GlobalObjectKey(0))),
+        new Container(child: new StatefulBuilder(
+          builder: (BuildContext context, StateSetter setState) {
+            nestedSetState = setState;
+            if (flag)
+              return new Container(key: const GlobalObjectKey(0));
+            return new Container();
+          },
+        )),
+      ],
+    ));
     nestedSetState(() { flag = true; });
     await tester.pump();
     final dynamic error = tester.takeException();

packages/flutter/test/widgets/image_test.dart

@@ -235,6 +235,7 @@ void main() {
     // of the Image changes and the MediaQuery widgets do not.
     await tester.pumpWidget(
       new Row(
+        textDirection: TextDirection.ltr,
         children: <Widget> [
           new MediaQuery(
             key: mediaQueryKey2,
@@ -263,6 +264,7 @@ void main() {
 
     await tester.pumpWidget(
       new Row(
+        textDirection: TextDirection.ltr,
         children: <Widget> [
           new MediaQuery(
             key: mediaQueryKey2,

packages/flutter/test/widgets/layout_builder_and_parent_data_test.dart

@@ -29,6 +29,7 @@ class SizeChangerState extends State<SizeChanger> {
   @override
   Widget build(BuildContext context) {
     return new Row(
+      textDirection: TextDirection.ltr,
       children: <Widget>[
         new SizedBox(
           height: _flag ? 50.0 : 100.0,

packages/flutter/test/widgets/overflow_box_test.dart

@@ -42,7 +42,7 @@ void main() {
         .where((DiagnosticsNode n) => !n.hidden)
         .map((DiagnosticsNode n) => n.toString()).toList();
     expect(description, <String>[
-      'alignment: FractionalOffset(0.5, 0.5)',
+      'alignment: FractionalOffset.center',
       'minWidth: 1.0',
       'maxWidth: 2.0',
       'minHeight: 3.0',

packages/flutter/test/widgets/overlay_test.dart

@@ -43,7 +43,7 @@ void main() {
         ' ╎ │   size)\n'
         ' ╎ │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
         ' ╎ │ size: Size(800.0, 600.0)\n'
-        ' ╎ │ alignment: FractionalOffset(0.0, 0.0)\n'
+        ' ╎ │ alignment: FractionalOffset.topLeft\n'
         ' ╎ │ fit: expand\n'
         ' ╎ │ overflow: clip\n'
         ' ╎ │\n'
@@ -112,7 +112,7 @@ void main() {
           ' ╎ │   size)\n'
           ' ╎ │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
           ' ╎ │ size: Size(800.0, 600.0)\n'
-          ' ╎ │ alignment: FractionalOffset(0.0, 0.0)\n'
+          ' ╎ │ alignment: FractionalOffset.topLeft\n'
           ' ╎ │ fit: expand\n'
           ' ╎ │ overflow: clip\n'
           ' ╎ │\n'