Port most of widgets to AnimationController

I've left transitions and enter_exit_transition out of this patch, but I've
converted the rest.

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

@@ -41,10 +41,9 @@ class Theme extends InheritedWidget {
   }
 }
 
-/// An animated value that interpolates [BoxConstraint]s.
-class AnimatedThemeDataValue extends AnimatedValue<ThemeData> {
-  AnimatedThemeDataValue(ThemeData begin, { ThemeData end, Curve curve, Curve reverseCurve })
-    : super(begin, end: end, curve: curve, reverseCurve: reverseCurve);
+/// An animated value that interpolates [ThemeData]s.
+class ThemeDataTween extends Tween<ThemeData> {
+  ThemeDataTween({ ThemeData begin, ThemeData end }) : super(begin: begin, end: end);
 
   ThemeData lerp(double t) => ThemeData.lerp(begin, end, t);
 }
@@ -71,18 +70,18 @@ class AnimatedTheme extends AnimatedWidgetBase {
 }
 
 class _AnimatedThemeState extends AnimatedWidgetBaseState<AnimatedTheme> {
-  AnimatedThemeDataValue _data;
+  ThemeDataTween _data;
 
-  void forEachVariable(VariableVisitor visitor) {
+  void forEachTween(TweenVisitor visitor) {
     // TODO(ianh): Use constructor tear-offs when it becomes possible
-    _data = visitor(_data, config.data, (dynamic value) => new AnimatedThemeDataValue(value));
+    _data = visitor(_data, config.data, (dynamic value) => new ThemeDataTween(begin: value));
     assert(_data != null);
   }
 
   Widget build(BuildContext context) {
     return new Theme(
       child: config.child,
-      data: _data.value
+      data: _data.evaluate(animation)
     );
   }
 

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

@@ -72,23 +72,23 @@ class Dismissable extends StatefulComponent {
 class _DismissableState extends State<Dismissable> {
   void initState() {
     super.initState();
-    _dismissPerformance = new Performance(duration: _kCardDismissDuration);
-    _dismissPerformance.addStatusListener((PerformanceStatus status) {
+    _dismissController = new AnimationController(duration: _kCardDismissDuration);
+    _dismissController.addStatusListener((PerformanceStatus status) {
       if (status == PerformanceStatus.completed)
         _handleDismissCompleted();
     });
   }
 
-  Performance _dismissPerformance;
-  Performance _resizePerformance;
+  AnimationController _dismissController;
+  AnimationController _resizeController;
 
   Size _size;
   double _dragExtent = 0.0;
   bool _dragUnderway = false;
 
   void dispose() {
-    _dismissPerformance?.stop();
-    _resizePerformance?.stop();
+    _dismissController?.stop();
+    _resizeController?.stop();
     super.dispose();
   }
 
@@ -101,11 +101,11 @@ class _DismissableState extends State<Dismissable> {
 
   void _handleDismissCompleted() {
     if (!_dragUnderway)
-      _startResizePerformance();
+      _startResizeAnimation();
   }
 
   bool get _isActive {
-    return _size != null && (_dragUnderway || _dismissPerformance.isAnimating);
+    return _size != null && (_dragUnderway || _dismissController.isAnimating);
   }
 
   void _maybeCallOnResized() {
@@ -118,21 +118,20 @@ class _DismissableState extends State<Dismissable> {
       config.onDismissed();
   }
 
-  void _startResizePerformance() {
+  void _startResizeAnimation() {
     assert(_size != null);
-    assert(_dismissPerformance != null);
-    assert(_dismissPerformance.isCompleted);
-    assert(_resizePerformance == null);
+    assert(_dismissController != null);
+    assert(_dismissController.isCompleted);
+    assert(_resizeController == null);
     setState(() {
-      _resizePerformance = new Performance()
-        ..duration = _kCardResizeDuration
+      _resizeController = new AnimationController(duration: _kCardResizeDuration)
         ..addListener(_handleResizeProgressChanged);
-      _resizePerformance.play();
+      _resizeController.forward();
     });
   }
 
   void _handleResizeProgressChanged() {
-    if (_resizePerformance.isCompleted)
+    if (_resizeController.isCompleted)
       _maybeCallOnDismissed();
     else
       _maybeCallOnResized();
@@ -141,18 +140,18 @@ class _DismissableState extends State<Dismissable> {
   void _handleDragStart(_) {
     setState(() {
       _dragUnderway = true;
-      if (_dismissPerformance.isAnimating) {
-        _dragExtent = _dismissPerformance.progress * _size.width * _dragExtent.sign;
-        _dismissPerformance.stop();
+      if (_dismissController.isAnimating) {
+        _dragExtent = _dismissController.value * _size.width * _dragExtent.sign;
+        _dismissController.stop();
       } else {
         _dragExtent = 0.0;
-        _dismissPerformance.progress = 0.0;
+        _dismissController.value = 0.0;
       }
     });
   }
 
   void _handleDragUpdate(double delta) {
-    if (!_isActive || _dismissPerformance.isAnimating)
+    if (!_isActive || _dismissController.isAnimating)
       return;
 
     double oldDragExtent = _dragExtent;
@@ -180,11 +179,11 @@ class _DismissableState extends State<Dismissable> {
         // Rebuild to update the new drag endpoint.
         // The sign of _dragExtent is part of our build state;
         // the actual value is not, it's just used to configure
-        // the performances.
+        // the animations.
       });
     }
-    if (!_dismissPerformance.isAnimating)
-      _dismissPerformance.progress = _dragExtent.abs() / _size.width;
+    if (!_dismissController.isAnimating)
+      _dismissController.value = _dragExtent.abs() / _size.width;
   }
 
   bool _isFlingGesture(ui.Offset velocity) {
@@ -217,20 +216,20 @@ class _DismissableState extends State<Dismissable> {
   }
 
   void _handleDragEnd(ui.Offset velocity) {
-    if (!_isActive || _dismissPerformance.isAnimating)
+    if (!_isActive || _dismissController.isAnimating)
       return;
     setState(() {
       _dragUnderway = false;
-      if (_dismissPerformance.isCompleted) {
-        _startResizePerformance();
+      if (_dismissController.isCompleted) {
+        _startResizeAnimation();
       } else if (_isFlingGesture(velocity)) {
         double flingVelocity = _directionIsYAxis ? velocity.dy : velocity.dx;
         _dragExtent = flingVelocity.sign;
-        _dismissPerformance.fling(velocity: flingVelocity.abs() * _kFlingVelocityScale);
-      } else if (_dismissPerformance.progress > _kDismissCardThreshold) {
-        _dismissPerformance.forward();
+        _dismissController.fling(velocity: flingVelocity.abs() * _kFlingVelocityScale);
+      } else if (_dismissController.value > _kDismissCardThreshold) {
+        _dismissController.forward();
       } else {
-        _dismissPerformance.reverse();
+        _dismissController.reverse();
       }
     });
   }
@@ -250,20 +249,26 @@ class _DismissableState extends State<Dismissable> {
   }
 
   Widget build(BuildContext context) {
-    if (_resizePerformance != null) {
+    if (_resizeController != null) {
       // make sure you remove this widget once it's been dismissed!
-      assert(_resizePerformance.status == PerformanceStatus.forward);
+      assert(_resizeController.status == PerformanceStatus.forward);
 
-      AnimatedValue<double> squashAxisExtent = new AnimatedValue<double>(
-        _directionIsYAxis ? _size.width : _size.height,
-        end: 0.0,
+      Animated<double> squashAxisExtent = new Tween<double>(
+        begin: _directionIsYAxis ? _size.width : _size.height,
+        end: 0.0
+      ).animate(new CurvedAnimation(
+        parent: _resizeController,
         curve: _kCardResizeTimeCurve
-      );
-
-      return new SquashTransition(
-        performance: _resizePerformance.view,
-        width: _directionIsYAxis ? squashAxisExtent : null,
-        height: !_directionIsYAxis ? squashAxisExtent : null
+      ));
+
+      return new AnimatedBuilder(
+        animation: squashAxisExtent,
+        builder: (BuildContext context, Widget child) {
+          return new SizedBox(
+            width: _directionIsYAxis ? squashAxisExtent.value : null,
+            height: !_directionIsYAxis ? squashAxisExtent.value : null
+          );
+        }
       );
     }
 
@@ -278,11 +283,10 @@ class _DismissableState extends State<Dismissable> {
       child: new SizeObserver(
         onSizeChanged: _handleSizeChanged,
         child: new SlideTransition(
-          performance: _dismissPerformance.view,
-          position: new AnimatedValue<FractionalOffset>(
-            FractionalOffset.zero,
+          position: new Tween<FractionalOffset>(
+            begin: FractionalOffset.zero,
             end: _activeCardDragEndPoint
-          ),
+          ).animate(_dismissController),
           child: config.child
         )
       )

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

@@ -378,7 +378,7 @@ class HeroParty {
 
   Animated<double> _currentAnimation;
 
-  void _clearCurrentPerformance() {
+  void _clearCurrentAnimation() {
     _currentAnimation?.removeStatusListener(_handleUpdate);
     _currentAnimation = null;
   }
@@ -386,7 +386,7 @@ class HeroParty {
   void setAnimation(Animated<double> animation) {
     assert(animation != null || _heroes.length == 0);
     if (animation != _currentAnimation) {
-      _clearCurrentPerformance();
+      _clearCurrentAnimation();
       _currentAnimation = animation;
       _currentAnimation?.addStatusListener(_handleUpdate);
     }
@@ -402,7 +402,7 @@ class HeroParty {
           source._resetChild();
       }
       _heroes.clear();
-      _clearCurrentPerformance();
+      _clearCurrentAnimation();
       if (onQuestFinished != null)
         onQuestFinished();
     }

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

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:ui' as ui;
 
 import 'package:flutter/animation.dart';
 import 'package:flutter/rendering.dart';
@@ -42,7 +41,7 @@ class MimicOverlayEntry {
   // Animation state
   GlobalKey _targetKey;
   Curve _curve;
-  Performance _performance;
+  AnimationController _controller;
 
   /// Animate the entry to the location of the widget that has the given target key.
   ///
@@ -63,10 +62,10 @@ class MimicOverlayEntry {
     _targetKey = targetKey;
     _curve = curve;
     // TODO(abarth): Support changing the animation target when in flight.
-    assert(_performance == null);
-    _performance = new Performance(duration: duration)
+    assert(_controller == null);
+    _controller = new AnimationController(duration: duration)
       ..addListener(_overlayEntry.markNeedsBuild);
-    return _performance.play();
+    return _controller.forward();
   }
 
   /// Cause the overlay entry to rebuild during the next pipeline flush.
@@ -84,8 +83,8 @@ class MimicOverlayEntry {
   void dispose() {
     _targetKey = null;
     _curve = null;
-    _performance?.stop();
-    _performance = null;
+    _controller?.stop();
+    _controller = null;
     _key.stopMimic();
     _key = null;
     _overlayEntry.remove();
@@ -98,16 +97,14 @@ class MimicOverlayEntry {
     Rect globalBounds = _initialGlobalBounds;
     Point globalPosition = globalBounds.topLeft;
     if (_targetKey != null) {
-      assert(_performance != null);
+      assert(_controller != null);
       assert(_curve != null);
       RenderBox box = _targetKey.currentContext?.findRenderObject();
       if (box != null) {
         // TODO(abarth): Handle the case where the transform here isn't just a translation.
         Point localPosition = box.localToGlobal(Point.origin);
-        double t = _curve.transform(_performance.progress);
-        // TODO(abarth): Add Point.lerp.
-        globalPosition = new Point(ui.lerpDouble(globalPosition.x, localPosition.x, t),
-                                 ui.lerpDouble(globalPosition.y, localPosition.y, t));
+        double t = _curve.transform(_controller.value);
+        globalPosition = Point.lerp(globalPosition, localPosition, t);
       }
     }
 

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

@@ -96,7 +96,7 @@ abstract class TransitionRoute<T> extends OverlayRoute<T> {
   Animated<double> _animation;
   AnimationController _controller;
 
-  /// Called to create the Performance object that will drive the transitions to
+  /// Called to create the animation controller that will drive the transitions to
   /// this route from the previous one, and back to the previous route from this
   /// one.
   AnimationController createAnimationController() {
@@ -105,8 +105,8 @@ abstract class TransitionRoute<T> extends OverlayRoute<T> {
     return new AnimationController(duration: duration, debugLabel: debugLabel);
   }
 
-  /// Called to create the PerformanceView that exposes the current progress of
-  /// the transition controlled by the Performance object created by
+  /// Called to create the animation that exposes the current progress of
+  /// the transition controlled by the animation controller created by
   /// [createAnimationController()].
   Animated<double> createAnimation() {
     assert(_controller != null);
@@ -166,32 +166,32 @@ abstract class TransitionRoute<T> extends OverlayRoute<T> {
   }
 
   void didPopNext(Route nextRoute) {
-    _updateForwardPerformance(nextRoute);
+    _updateForwardAnimation(nextRoute);
     super.didPopNext(nextRoute);
   }
 
   void didChangeNext(Route nextRoute) {
-    _updateForwardPerformance(nextRoute);
+    _updateForwardAnimation(nextRoute);
     super.didChangeNext(nextRoute);
   }
 
-  void _updateForwardPerformance(Route nextRoute) {
+  void _updateForwardAnimation(Route nextRoute) {
     if (nextRoute is TransitionRoute && canTransitionTo(nextRoute) && nextRoute.canTransitionFrom(this)) {
       Animated<double> current = _forwardAnimation.masterAnimation;
       if (current != null) {
         if (current is TrainHoppingAnimation) {
-          TrainHoppingAnimation newPerformance;
-          newPerformance = new TrainHoppingAnimation(
+          TrainHoppingAnimation newAnimation;
+          newAnimation = new TrainHoppingAnimation(
             current.currentTrain,
             nextRoute.animation,
             onSwitchedTrain: () {
-              assert(_forwardAnimation.masterAnimation == newPerformance);
-              assert(newPerformance.currentTrain == nextRoute.animation);
-              _forwardAnimation.masterAnimation = newPerformance.currentTrain;
-              newPerformance.dispose();
+              assert(_forwardAnimation.masterAnimation == newAnimation);
+              assert(newAnimation.currentTrain == nextRoute.animation);
+              _forwardAnimation.masterAnimation = newAnimation.currentTrain;
+              newAnimation.dispose();
             }
           );
-          _forwardAnimation.masterAnimation = newPerformance;
+          _forwardAnimation.masterAnimation = newAnimation;
           current.dispose();
         } else {
           _forwardAnimation.masterAnimation = new TrainHoppingAnimation(current, nextRoute.animation);
@@ -322,7 +322,7 @@ class _ModalScopeState extends State<_ModalScope> {
 
   void _animationStatusChanged(PerformanceStatus status) {
     setState(() {
-      // The performances' states are our build state, and they changed already.
+      // The animation's states are our build state, and they changed already.
     });
   }
 

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

@@ -24,24 +24,24 @@ abstract class StatusTransitionComponent extends StatefulComponent {
 class _StatusTransitionState extends State<StatusTransitionComponent> {
   void initState() {
     super.initState();
-    config.animation.addStatusListener(_performanceStatusChanged);
+    config.animation.addStatusListener(_animationStatusChanged);
   }
 
   void didUpdateConfig(StatusTransitionComponent oldConfig) {
     if (config.animation != oldConfig.animation) {
-      oldConfig.animation.removeStatusListener(_performanceStatusChanged);
-      config.animation.addStatusListener(_performanceStatusChanged);
+      oldConfig.animation.removeStatusListener(_animationStatusChanged);
+      config.animation.addStatusListener(_animationStatusChanged);
     }
   }
 
   void dispose() {
-    config.animation.removeStatusListener(_performanceStatusChanged);
+    config.animation.removeStatusListener(_animationStatusChanged);
     super.dispose();
   }
 
-  void _performanceStatusChanged(PerformanceStatus status) {
+  void _animationStatusChanged(PerformanceStatus status) {
     setState(() {
-      // The performance's state is our build state, and it changed already.
+      // The animation's state is our build state, and it changed already.
     });
   }
 

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

@@ -126,23 +126,25 @@ abstract class TransitionWithChild extends TransitionComponent {
   Widget buildWithChild(BuildContext context, Widget child);
 }
 
-class SlideTransition extends TransitionWithChild {
+class SlideTransition extends AnimatedComponent {
   SlideTransition({
     Key key,
-    this.position,
+    Animated<FractionalOffset> position,
     PerformanceView performance,
     this.transformHitTests: true,
-    Widget child
-  }) : super(key: key,
-             performance: performance,
-             child: child);
+    this.child
+  }) : position = position, super(key: key, animation: position);
 
-  final AnimatedValue<FractionalOffset> position;
-  bool transformHitTests;
+  final Animated<FractionalOffset> position;
+  final bool transformHitTests;
+  final Widget child;
 
-  Widget buildWithChild(BuildContext context, Widget child) {
-    performance.updateVariable(position);
-    return new FractionalTranslation(translation: position.value, transformHitTests: transformHitTests, child: child);
+  Widget build(BuildContext context) {
+    return new FractionalTranslation(
+      translation: position.value,
+      transformHitTests: transformHitTests,
+      child: child
+    );
   }
 }