diff --git a/examples/fitness/lib/feed.dart b/examples/fitness/lib/feed.dart
index 221b7056f8..b7555f92e6 100644
--- a/examples/fitness/lib/feed.dart
+++ b/examples/fitness/lib/feed.dart
@@ -60,7 +60,7 @@ class FeedFragment extends StatefulComponent {
 class FeedFragmentState extends State<FeedFragment> {
   FitnessMode _fitnessMode = FitnessMode.feed;
 
-  AnimationStatus _snackBarStatus = AnimationStatus.dismissed;
+  PerformanceStatus _snackBarStatus = PerformanceStatus.dismissed;
   bool _isShowingSnackBar = false;
 
   void _handleFitnessModeChange(FitnessMode value) {
@@ -126,7 +126,7 @@ class FeedFragmentState extends State<FeedFragment> {
     setState(() {
       _undoItem = item;
       _isShowingSnackBar = true;
-      _snackBarStatus = AnimationStatus.forward;
+      _snackBarStatus = PerformanceStatus.forward;
     });
   }
 
@@ -207,13 +207,13 @@ class FeedFragmentState extends State<FeedFragment> {
   }
 
   Widget buildSnackBar() {
-    if (_snackBarStatus == AnimationStatus.dismissed)
+    if (_snackBarStatus == PerformanceStatus.dismissed)
       return null;
     return new SnackBar(
       showing: _isShowingSnackBar,
       content: new Text("Item deleted."),
       actions: [new SnackBarAction(label: "UNDO", onPressed: _handleUndo)],
-      onDismissed: () { setState(() { _snackBarStatus = AnimationStatus.dismissed; }); }
+      onDismissed: () { setState(() { _snackBarStatus = PerformanceStatus.dismissed; }); }
     );
   }
 
diff --git a/examples/stocks/lib/stock_home.dart b/examples/stocks/lib/stock_home.dart
index 80e399ce8b..091e379f67 100644
--- a/examples/stocks/lib/stock_home.dart
+++ b/examples/stocks/lib/stock_home.dart
@@ -25,7 +25,7 @@ class StockHomeState extends State<StockHome> {
   bool _isSearching = false;
   String _searchQuery;
 
-  AnimationStatus _snackBarStatus = AnimationStatus.dismissed;
+  PerformanceStatus _snackBarStatus = PerformanceStatus.dismissed;
   bool _isSnackBarShowing = false;
 
   void _handleSearchBegin() {
@@ -224,20 +224,20 @@ class StockHomeState extends State<StockHome> {
 
   GlobalKey snackBarKey = new GlobalKey(label: 'snackbar');
   Widget buildSnackBar() {
-    if (_snackBarStatus == AnimationStatus.dismissed)
+    if (_snackBarStatus == PerformanceStatus.dismissed)
       return null;
     return new SnackBar(
       showing: _isSnackBarShowing,
       content: new Text("Stock purchased!"),
       actions: [new SnackBarAction(label: "UNDO", onPressed: _handleUndo)],
-      onDismissed: () { setState(() { _snackBarStatus = AnimationStatus.dismissed; }); }
+      onDismissed: () { setState(() { _snackBarStatus = PerformanceStatus.dismissed; }); }
     );
   }
 
   void _handleStockPurchased() {
     setState(() {
       _isSnackBarShowing = true;
-      _snackBarStatus = AnimationStatus.forward;
+      _snackBarStatus = PerformanceStatus.forward;
     });
   }
 
diff --git a/examples/widgets/progress_indicator.dart b/examples/widgets/progress_indicator.dart
index 1024d37138..e769784b46 100644
--- a/examples/widgets/progress_indicator.dart
+++ b/examples/widgets/progress_indicator.dart
@@ -13,7 +13,7 @@ class ProgressIndicatorApp extends StatefulComponent {
 class ProgressIndicatorAppState extends State<ProgressIndicatorApp> {
   void initState() {
     super.initState();
-    valueAnimation = new ValueAnimation<double>()
+    valueAnimation = new ValuePerformance<double>()
       ..duration = const Duration(milliseconds: 1500)
       ..variable = new AnimatedValue<double>(
         0.0,
@@ -22,15 +22,15 @@ class ProgressIndicatorAppState extends State<ProgressIndicatorApp> {
         reverseCurve: ease,
         interval: new Interval(0.0, 0.9)
       );
-    valueAnimation.addStatusListener((AnimationStatus status) {
-      if (status == AnimationStatus.dismissed || status == AnimationStatus.completed)
+    valueAnimation.addStatusListener((PerformanceStatus status) {
+      if (status == PerformanceStatus.dismissed || status == PerformanceStatus.completed)
         reverseValueAnimationDirection();
     });
     valueAnimation.play(valueAnimationDirection);
   }
 
-  ValueAnimation<double> valueAnimation;
-  Direction valueAnimationDirection = Direction.forward;
+  ValuePerformance<double> valueAnimation;
+  AnimationDirection valueAnimationDirection = AnimationDirection.forward;
 
   void handleTap() {
     setState(() {
@@ -43,9 +43,9 @@ class ProgressIndicatorAppState extends State<ProgressIndicatorApp> {
   }
 
   void reverseValueAnimationDirection() {
-    valueAnimationDirection = (valueAnimationDirection == Direction.forward)
-      ? Direction.reverse
-      : Direction.forward;
+    valueAnimationDirection = (valueAnimationDirection == AnimationDirection.forward)
+      ? AnimationDirection.reverse
+      : AnimationDirection.forward;
     valueAnimation.play(valueAnimationDirection);
   }
 
diff --git a/packages/flutter/lib/animation.dart b/packages/flutter/lib/animation.dart
index 564f8cdae4..e9c75373b7 100644
--- a/packages/flutter/lib/animation.dart
+++ b/packages/flutter/lib/animation.dart
@@ -8,7 +8,7 @@
 library animation;
 
 export 'src/animation/animated_value.dart';
-export 'src/animation/animation_performance.dart';
+export 'src/animation/performance.dart';
 export 'src/animation/clamped_simulation.dart';
 export 'src/animation/curves.dart';
 export 'src/animation/forces.dart';
diff --git a/packages/flutter/lib/src/animation/animated_value.dart b/packages/flutter/lib/src/animation/animated_value.dart
index 732c8f2855..f42c4b8910 100644
--- a/packages/flutter/lib/src/animation/animated_value.dart
+++ b/packages/flutter/lib/src/animation/animated_value.dart
@@ -7,7 +7,7 @@ import 'dart:sky' show Color, Rect;
 import 'package:sky/src/animation/curves.dart';
 
 /// The direction in which an animation is running
-enum Direction {
+enum AnimationDirection {
   /// The animation is running from beginning to end
   forward,
 
@@ -17,11 +17,11 @@ enum Direction {
 
 /// An interface describing a variable that changes as an animation progresses.
 ///
-/// AnimatedVariables, by convention, must be cheap to create. This allows them to be used in
-/// build functions in Widgets.
-abstract class AnimatedVariable {
+/// Animatable objects, by convention, must be cheap to create. This allows them
+/// to be used in build functions in Widgets.
+abstract class Animatable {
   /// Update the variable to a given time in an animation that is running in the given direction
-  void setProgress(double t, Direction direction);
+  void setProgress(double t, AnimationDirection direction);
   String toString();
 }
 
@@ -53,7 +53,7 @@ class AnimationTiming {
   Curve reverseCurve;
 
   /// Applies this timing to the given animation clock value in the given direction
-  double transform(double t, Direction direction) {
+  double transform(double t, AnimationDirection direction) {
     Interval interval = _getInterval(direction);
     if (interval != null)
       t = interval.transform(t);
@@ -65,19 +65,19 @@ class AnimationTiming {
     return _applyCurve(t, direction);
   }
 
-  Interval _getInterval(Direction direction) {
-    if (direction == Direction.forward || reverseInterval == null)
+  Interval _getInterval(AnimationDirection direction) {
+    if (direction == AnimationDirection.forward || reverseInterval == null)
       return interval;
     return reverseInterval;
   }
 
-  Curve _getCurve(Direction direction) {
-    if (direction == Direction.forward || reverseCurve == null)
+  Curve _getCurve(AnimationDirection direction) {
+    if (direction == AnimationDirection.forward || reverseCurve == null)
       return curve;
     return reverseCurve;
   }
 
-  double _applyCurve(double t, Direction direction) {
+  double _applyCurve(double t, AnimationDirection direction) {
     Curve curve = _getCurve(direction);
     if (curve == null)
       return t;
@@ -86,7 +86,7 @@ class AnimationTiming {
 }
 
 /// An animated variable with a concrete type
-class AnimatedValue<T extends dynamic> extends AnimationTiming implements AnimatedVariable {
+class AnimatedValue<T extends dynamic> extends AnimationTiming implements Animatable {
   AnimatedValue(this.begin, { this.end, Interval interval, Interval reverseInterval, Curve curve, Curve reverseCurve })
     : super(interval: interval, reverseInterval: reverseInterval, curve: curve, reverseCurve: reverseCurve) {
     value = begin;
@@ -105,7 +105,7 @@ class AnimatedValue<T extends dynamic> extends AnimationTiming implements Animat
   T lerp(double t) => begin + (end - begin) * t;
 
   /// Updates the value of this variable according to the given animation clock value and direction
-  void setProgress(double t, Direction direction) {
+  void setProgress(double t, AnimationDirection direction) {
     if (end != null) {
       t = transform(t, direction);
       if (t == 0.0)
@@ -120,24 +120,6 @@ class AnimatedValue<T extends dynamic> extends AnimationTiming implements Animat
   String toString() => 'AnimatedValue(begin=$begin, end=$end, value=$value)';
 }
 
-/// A list of animated variables
-class AnimatedList extends AnimationTiming implements AnimatedVariable {
-  /// The list of variables contained in the list
-  List<AnimatedVariable> variables;
-
-  AnimatedList(this.variables, { Interval interval, Interval reverseInterval, Curve curve, Curve reverseCurve })
-    : super(interval: interval, reverseInterval: reverseInterval, curve: curve, reverseCurve: reverseCurve);
-
-  // Updates the value of all the variables in the list according to the given animation clock value and direction
-  void setProgress(double t, Direction direction) {
-    double adjustedTime = transform(t, direction);
-    for (AnimatedVariable variable in variables)
-      variable.setProgress(adjustedTime, direction);
-  }
-
-  String toString() => 'AnimatedList([$variables])';
-}
-
 /// An animated variable containing a color
 ///
 /// This class specializes the interpolation of AnimatedValue<Color> to be
@@ -153,8 +135,8 @@ class AnimatedColorValue extends AnimatedValue<Color> {
 ///
 /// This class specializes the interpolation of AnimatedValue<Rect> to be
 /// appropriate for rectangles.
-class AnimatedRect extends AnimatedValue<Rect> {
-  AnimatedRect(Rect begin, { Rect end, Interval interval, Interval reverseInterval, Curve curve, Curve reverseCurve })
+class AnimatedRectValue extends AnimatedValue<Rect> {
+  AnimatedRectValue(Rect begin, { Rect end, Interval interval, Interval reverseInterval, Curve curve, Curve reverseCurve })
     : super(begin, end: end, interval: interval, reverseInterval: reverseInterval, curve: curve, reverseCurve: reverseCurve);
 
   Rect lerp(double t) => Rect.lerp(begin, end, t);
diff --git a/packages/flutter/lib/src/animation/animation_performance.dart b/packages/flutter/lib/src/animation/performance.dart
similarity index 66%
rename from packages/flutter/lib/src/animation/animation_performance.dart
rename to packages/flutter/lib/src/animation/performance.dart
index e9690daf2b..92c77f8b59 100644
--- a/packages/flutter/lib/src/animation/animation_performance.dart
+++ b/packages/flutter/lib/src/animation/performance.dart
@@ -9,7 +9,7 @@ import 'package:sky/src/animation/forces.dart';
 import 'package:sky/src/animation/simulation_stepper.dart';
 
 /// The status of an animation
-enum AnimationStatus {
+enum PerformanceStatus {
   /// The animation is stopped at the beginning
   dismissed,
 
@@ -23,27 +23,27 @@ enum AnimationStatus {
   completed,
 }
 
-typedef void AnimationPerformanceListener();
-typedef void AnimationPerformanceStatusListener(AnimationStatus status);
+typedef void PerformanceListener();
+typedef void PerformanceStatusListener(PerformanceStatus status);
 
-/// An interface that is implemented by [AnimationPerformance] that exposes a
+/// An interface that is implemented by [Performance] that exposes a
 /// read-only view of the underlying performance. This is used by classes that
 /// want to watch a performance but should not be able to change the
 /// performance's state.
-abstract class WatchableAnimationPerformance {
+abstract class PerformanceView {
   /// Update the given variable according to the current progress of the performance
-  void updateVariable(AnimatedVariable variable);
+  void updateVariable(Animatable variable);
   /// Calls the listener every time the progress of the performance changes
-  void addListener(AnimationPerformanceListener listener);
+  void addListener(PerformanceListener listener);
   /// Stop calling the listener every time the progress of the performance changes
-  void removeListener(AnimationPerformanceListener listener);
+  void removeListener(PerformanceListener listener);
   /// Calls listener every time the status of the performance changes
-  void addStatusListener(AnimationPerformanceStatusListener listener);
+  void addStatusListener(PerformanceStatusListener listener);
   /// Stops calling the listener every time the status of the performance changes
-  void removeStatusListener(AnimationPerformanceStatusListener listener);
+  void removeStatusListener(PerformanceStatusListener listener);
 }
 
-/// A timeline that can be reversed and used to update [AnimatedVariable]s.
+/// A timeline that can be reversed and used to update [Animatable]s.
 ///
 /// For example, a performance may handle an animation of a menu opening by
 /// sliding and fading in (changing Y value and opacity) over .5 seconds. The
@@ -51,30 +51,30 @@ abstract class WatchableAnimationPerformance {
 /// may also take direct control of the timeline by manipulating [progress], or
 /// [fling] the timeline causing a physics-based simulation to take over the
 /// progression.
-class AnimationPerformance implements WatchableAnimationPerformance {
-  AnimationPerformance({ this.duration, double progress }) {
+class Performance implements PerformanceView {
+  Performance({ this.duration, double progress }) {
     _timeline = new SimulationStepper(_tick);
     if (progress != null)
       _timeline.value = progress.clamp(0.0, 1.0);
   }
 
-  /// Returns a [WatchableAnimationPerformance] for this performance,
+  /// Returns a [PerformanceView] for this performance,
   /// so that a pointer to this object can be passed around without
   /// allowing users of that pointer to mutate the AnimationPerformance state.
-  WatchableAnimationPerformance get view => this;
+  PerformanceView get view => this;
 
   /// The length of time this performance should last
   Duration duration;
 
   SimulationStepper _timeline;
-  Direction _direction;
+  AnimationDirection _direction;
 
   /// The direction used to select the current curve
   ///
   /// Curve direction is only reset when we hit the beginning or the end of the
   /// timeline to avoid discontinuities in the value of any variables this
   /// performance is used to animate.
-  Direction _curveDirection;
+  AnimationDirection _curveDirection;
 
   /// If non-null, animate with this timing instead of a linear timing
   AnimationTiming timing;
@@ -95,45 +95,45 @@ class AnimationPerformance implements WatchableAnimationPerformance {
   }
 
   /// Whether this animation is stopped at the beginning
-  bool get isDismissed => status == AnimationStatus.dismissed;
+  bool get isDismissed => status == PerformanceStatus.dismissed;
 
   /// Whether this animation is stopped at the end
-  bool get isCompleted => status == AnimationStatus.completed;
+  bool get isCompleted => status == PerformanceStatus.completed;
 
   /// Whether this animation is currently animating in either the forward or reverse direction
   bool get isAnimating => _timeline.isAnimating;
 
   /// The current status of this animation
-  AnimationStatus get status {
+  PerformanceStatus get status {
     if (!isAnimating && progress == 1.0)
-      return AnimationStatus.completed;
+      return PerformanceStatus.completed;
     if (!isAnimating && progress == 0.0)
-      return AnimationStatus.dismissed;
-    return _direction == Direction.forward ?
-        AnimationStatus.forward :
-        AnimationStatus.reverse;
+      return PerformanceStatus.dismissed;
+    return _direction == AnimationDirection.forward ?
+        PerformanceStatus.forward :
+        PerformanceStatus.reverse;
   }
 
   /// Update the given varaible according to the current progress of this performance
-  void updateVariable(AnimatedVariable variable) {
+  void updateVariable(Animatable variable) {
     variable.setProgress(_curvedProgress, _curveDirection);
   }
 
   /// Start running this animation forwards (towards the end)
-  Future forward() => play(Direction.forward);
+  Future forward() => play(AnimationDirection.forward);
 
   /// Start running this animation in reverse (towards the beginning)
-  Future reverse() => play(Direction.reverse);
+  Future reverse() => play(AnimationDirection.reverse);
 
   /// Start running this animation in the given direction
-  Future play([Direction direction = Direction.forward]) {
+  Future play([AnimationDirection direction = AnimationDirection.forward]) {
     _direction = direction;
     return resume();
   }
 
-  /// Start running this animation in the most recently direction
+  /// Start running this animation in the most recent direction
   Future resume() {
-    return _animateTo(_direction == Direction.forward ? 1.0 : 0.0);
+    return _animateTo(_direction == AnimationDirection.forward ? 1.0 : 0.0);
   }
 
   /// Stop running this animation
@@ -149,46 +149,46 @@ class AnimationPerformance implements WatchableAnimationPerformance {
   Future fling({double velocity: 1.0, Force force}) {
     if (force == null)
       force = kDefaultSpringForce;
-    _direction = velocity < 0.0 ? Direction.reverse : Direction.forward;
+    _direction = velocity < 0.0 ? AnimationDirection.reverse : AnimationDirection.forward;
     return _timeline.animateWith(force.release(progress, velocity));
   }
 
-  final List<AnimationPerformanceListener> _listeners = new List<AnimationPerformanceListener>();
+  final List<PerformanceListener> _listeners = new List<PerformanceListener>();
 
   /// Calls the listener every time the progress of this performance changes
-  void addListener(AnimationPerformanceListener listener) {
+  void addListener(PerformanceListener listener) {
     _listeners.add(listener);
   }
 
   /// Stop calling the listener every time the progress of this performance changes
-  void removeListener(AnimationPerformanceListener listener) {
+  void removeListener(PerformanceListener listener) {
     _listeners.remove(listener);
   }
 
   void _notifyListeners() {
-    List<AnimationPerformanceListener> localListeners = new List<AnimationPerformanceListener>.from(_listeners);
-    for (AnimationPerformanceListener listener in localListeners)
+    List<PerformanceListener> localListeners = new List<PerformanceListener>.from(_listeners);
+    for (PerformanceListener listener in localListeners)
       listener();
   }
 
-  final List<AnimationPerformanceStatusListener> _statusListeners = new List<AnimationPerformanceStatusListener>();
+  final List<PerformanceStatusListener> _statusListeners = new List<PerformanceStatusListener>();
 
   /// Calls listener every time the status of this performance changes
-  void addStatusListener(AnimationPerformanceStatusListener listener) {
+  void addStatusListener(PerformanceStatusListener listener) {
     _statusListeners.add(listener);
   }
 
   /// Stops calling the listener every time the status of this performance changes
-  void removeStatusListener(AnimationPerformanceStatusListener listener) {
+  void removeStatusListener(PerformanceStatusListener listener) {
     _statusListeners.remove(listener);
   }
 
-  AnimationStatus _lastStatus = AnimationStatus.dismissed;
+  PerformanceStatus _lastStatus = PerformanceStatus.dismissed;
   void _checkStatusChanged() {
-    AnimationStatus currentStatus = status;
+    PerformanceStatus currentStatus = status;
     if (currentStatus != _lastStatus) {
-      List<AnimationPerformanceStatusListener> localListeners = new List<AnimationPerformanceStatusListener>.from(_statusListeners);
-      for (AnimationPerformanceStatusListener listener in localListeners)
+      List<PerformanceStatusListener> localListeners = new List<PerformanceStatusListener>.from(_statusListeners);
+      for (PerformanceStatusListener listener in localListeners)
         listener(currentStatus);
     }
     _lastStatus = currentStatus;
@@ -196,7 +196,7 @@ class AnimationPerformance implements WatchableAnimationPerformance {
 
   void _updateCurveDirection() {
     if (status != _lastStatus) {
-      if (_lastStatus == AnimationStatus.dismissed || _lastStatus == AnimationStatus.completed)
+      if (_lastStatus == PerformanceStatus.dismissed || _lastStatus == PerformanceStatus.completed)
         _curveDirection = _direction;
     }
   }
@@ -221,8 +221,8 @@ class AnimationPerformance implements WatchableAnimationPerformance {
 }
 
 /// An animation performance with an animated variable with a concrete type
-class ValueAnimation<T> extends AnimationPerformance {
-  ValueAnimation({ this.variable, Duration duration, double progress }) :
+class ValuePerformance<T> extends Performance {
+  ValuePerformance({ this.variable, Duration duration, double progress }) :
     super(duration: duration, progress: progress);
 
   AnimatedValue<T> variable;
diff --git a/packages/flutter/lib/src/animation/simulation_stepper.dart b/packages/flutter/lib/src/animation/simulation_stepper.dart
index 39ff00c4e8..dee9cb0c73 100644
--- a/packages/flutter/lib/src/animation/simulation_stepper.dart
+++ b/packages/flutter/lib/src/animation/simulation_stepper.dart
@@ -28,7 +28,7 @@ class _TweenSimulation extends Simulation {
   double x(double timeInSeconds) {
     assert(timeInSeconds >= 0.0);
     final double t = (timeInSeconds / _durationInSeconds).clamp(0.0, 1.0);
-    _tween.setProgress(t, Direction.forward);
+    _tween.setProgress(t, AnimationDirection.forward);
     return _tween.value;
   }
 
diff --git a/packages/flutter/lib/src/painting/radial_reaction.dart b/packages/flutter/lib/src/painting/radial_reaction.dart
index c7997e4e5e..c2822cb9da 100644
--- a/packages/flutter/lib/src/painting/radial_reaction.dart
+++ b/packages/flutter/lib/src/painting/radial_reaction.dart
@@ -30,13 +30,13 @@ class RadialReaction {
     _outerOpacity = new AnimatedValue<double>(0.0, end: _kMaxOpacity, curve: easeOut);
     _innerCenter = new AnimatedValue<Point>(startPosition, end: center, curve: easeOut);
     _innerRadius = new AnimatedValue<double>(0.0, end: radius, curve: easeOut);
-    _showPerformance = new AnimationPerformance(duration: _kShowDuration)
+    _showPerformance = new Performance(duration: _kShowDuration)
       ..addListener(() {
         _showPerformance.updateVariable(_outerOpacity);
         _showPerformance.updateVariable(_innerCenter);
         _showPerformance.updateVariable(_innerRadius);
       });
-    _fade = new ValueAnimation<double>(
+    _fade = new ValuePerformance<double>(
       variable: new AnimatedValue(1.0, end: 0.0, curve: easeIn),
       duration: _kHideDuration
     );
@@ -48,14 +48,14 @@ class RadialReaction {
   /// The radius of the circle in which the reaction occurs
   final double radius;
 
-  AnimationPerformance _showPerformance;
+  Performance _showPerformance;
   AnimatedValue<double> _outerOpacity;
   AnimatedValue<Point> _innerCenter;
   AnimatedValue<double> _innerRadius;
 
   Future _showComplete;
 
-  ValueAnimation<double> _fade;
+  ValuePerformance<double> _fade;
 
   /// Show the reaction
   ///
diff --git a/packages/flutter/lib/src/rendering/toggleable.dart b/packages/flutter/lib/src/rendering/toggleable.dart
index 1a2bbae9ed..bd98d27cdb 100644
--- a/packages/flutter/lib/src/rendering/toggleable.dart
+++ b/packages/flutter/lib/src/rendering/toggleable.dart
@@ -24,15 +24,15 @@ abstract class RenderToggleable extends RenderConstrainedBox {
       : _value = value,
         _onChanged = onChanged,
         super(additionalConstraints: new BoxConstraints.tight(size)) {
-    _performance = new ValueAnimation<double>(
+    _performance = new ValuePerformance<double>(
       variable: new AnimatedValue<double>(0.0, end: 1.0, curve: easeIn, reverseCurve: easeOut),
       duration: _kToggleDuration,
       progress: _value ? 1.0 : 0.0
     )..addListener(markNeedsPaint);
   }
 
-  ValueAnimation<double> get performance => _performance;
-  ValueAnimation<double> _performance;
+  ValuePerformance<double> get performance => _performance;
+  ValuePerformance<double> _performance;
 
   double get position => _performance.value;
 
@@ -68,7 +68,7 @@ abstract class RenderToggleable extends RenderConstrainedBox {
     if (value == _value)
       return;
     _value = value;
-    performance.play(value ? Direction.forward : Direction.reverse);
+    performance.play(value ? AnimationDirection.forward : AnimationDirection.reverse);
   }
 
   ValueChanged get onChanged => _onChanged;
diff --git a/packages/flutter/lib/src/widgets/animated_component.dart b/packages/flutter/lib/src/widgets/animated_component.dart
index d9b27490c9..cf6acbc34f 100644
--- a/packages/flutter/lib/src/widgets/animated_component.dart
+++ b/packages/flutter/lib/src/widgets/animated_component.dart
@@ -9,13 +9,13 @@ abstract class AnimatedComponent extends StatefulComponent {
   const AnimatedComponent({ Key key, this.direction, this.duration }) : super(key: key);
 
   final Duration duration;
-  final Direction direction;
+  final AnimationDirection direction;
 }
 
 abstract class AnimatedState<T extends AnimatedComponent> extends State<T> {
   void initState() {
     super.initState();
-    _performance = new AnimationPerformance(duration: config.duration);
+    _performance = new Performance(duration: config.duration);
     performance.addStatusListener(_handleAnimationStatusChanged);
     if (buildDependsOnPerformance) {
       performance.addListener(() {
@@ -34,13 +34,13 @@ abstract class AnimatedState<T extends AnimatedComponent> extends State<T> {
       performance.play(config.direction);
   }
 
-  AnimationPerformance get performance => _performance;
-  AnimationPerformance _performance;
+  Performance get performance => _performance;
+  Performance _performance;
 
-  void _handleAnimationStatusChanged(AnimationStatus status) {
-    if (status == AnimationStatus.completed)
+  void _handleAnimationStatusChanged(PerformanceStatus status) {
+    if (status == PerformanceStatus.completed)
       handleCompleted();
-    else if (status == AnimationStatus.dismissed)
+    else if (status == PerformanceStatus.dismissed)
       handleDismissed();
   }
 
diff --git a/packages/flutter/lib/src/widgets/animated_container.dart b/packages/flutter/lib/src/widgets/animated_container.dart
index 291023e9f2..4d1f1d4de0 100644
--- a/packages/flutter/lib/src/widgets/animated_container.dart
+++ b/packages/flutter/lib/src/widgets/animated_container.dart
@@ -90,11 +90,11 @@ class AnimatedContainerState extends State<AnimatedContainer> {
   AnimatedValue<double> _width;
   AnimatedValue<double> _height;
 
-  AnimationPerformance _performance;
+  Performance _performance;
 
   void initState() {
     super.initState();
-    _performance = new AnimationPerformance(duration: config.duration)
+    _performance = new Performance(duration: config.duration)
       ..timing = new AnimationTiming(curve: config.curve)
       ..addListener(_updateAllVariables);
     _configAllVariables();
@@ -115,7 +115,7 @@ class AnimatedContainerState extends State<AnimatedContainer> {
     super.dispose();
   }
 
-  void _updateVariable(AnimatedVariable variable) {
+  void _updateVariable(Animatable variable) {
     if (variable != null)
       _performance.updateVariable(variable);
   }
diff --git a/packages/flutter/lib/src/widgets/dialog.dart b/packages/flutter/lib/src/widgets/dialog.dart
index ef142d0baa..54c2a6f174 100644
--- a/packages/flutter/lib/src/widgets/dialog.dart
+++ b/packages/flutter/lib/src/widgets/dialog.dart
@@ -141,7 +141,7 @@ class DialogRoute extends Route {
 
   Duration get transitionDuration => _kTransitionDuration;
   bool get opaque => false;
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) {
     return new FadeTransition(
       performance: performance,
       opacity: new AnimatedValue<double>(0.0, end: 1.0, curve: easeOut),
diff --git a/packages/flutter/lib/src/widgets/dismissable.dart b/packages/flutter/lib/src/widgets/dismissable.dart
index 6cb2a78e9b..d019580a68 100644
--- a/packages/flutter/lib/src/widgets/dismissable.dart
+++ b/packages/flutter/lib/src/widgets/dismissable.dart
@@ -50,15 +50,15 @@ class Dismissable extends StatefulComponent {
 class DismissableState extends State<Dismissable> {
   void initState() {
     super.initState();
-    _fadePerformance = new AnimationPerformance(duration: _kCardDismissFadeout);
-    _fadePerformance.addStatusListener((AnimationStatus status) {
-      if (status == AnimationStatus.completed)
+    _fadePerformance = new Performance(duration: _kCardDismissFadeout);
+    _fadePerformance.addStatusListener((PerformanceStatus status) {
+      if (status == PerformanceStatus.completed)
         _handleFadeCompleted();
     });
   }
 
-  AnimationPerformance _fadePerformance;
-  AnimationPerformance _resizePerformance;
+  Performance _fadePerformance;
+  Performance _resizePerformance;
 
   Size _size;
   double _dragExtent = 0.0;
@@ -97,7 +97,7 @@ class DismissableState extends State<Dismissable> {
     assert(_resizePerformance == null);
 
     setState(() {
-      _resizePerformance = new AnimationPerformance()
+      _resizePerformance = new Performance()
         ..duration = _kCardDismissResize
         ..addListener(_handleResizeProgressChanged);
       _resizePerformance.play();
@@ -221,7 +221,7 @@ class DismissableState extends State<Dismissable> {
   Widget build(BuildContext context) {
     if (_resizePerformance != null) {
       // make sure you remove this widget once it's been dismissed!
-      assert(_resizePerformance.status == AnimationStatus.forward);
+      assert(_resizePerformance.status == PerformanceStatus.forward);
 
       AnimatedValue<double> squashAxisExtent = new AnimatedValue<double>(
         _directionIsYAxis ? _size.width : _size.height,
diff --git a/packages/flutter/lib/src/widgets/drag_target.dart b/packages/flutter/lib/src/widgets/drag_target.dart
index accac1bb13..51800d7891 100644
--- a/packages/flutter/lib/src/widgets/drag_target.dart
+++ b/packages/flutter/lib/src/widgets/drag_target.dart
@@ -258,7 +258,7 @@ class DragRoute extends Route {
   bool get opaque => false;
   Duration get transitionDuration => const Duration();
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) {
     return new Positioned(
       left: _lastOffset.dx,
       top: _lastOffset.dy,
diff --git a/packages/flutter/lib/src/widgets/drawer.dart b/packages/flutter/lib/src/widgets/drawer.dart
index 5d980b391e..945542c5dd 100644
--- a/packages/flutter/lib/src/widgets/drawer.dart
+++ b/packages/flutter/lib/src/widgets/drawer.dart
@@ -55,15 +55,15 @@ class Drawer extends StatefulComponent {
 class DrawerState extends State<Drawer> {
   void initState() {
     super.initState();
-    _performance = new AnimationPerformance(duration: _kBaseSettleDuration)
-      ..addStatusListener((AnimationStatus status) {
-        if (status == AnimationStatus.dismissed)
+    _performance = new Performance(duration: _kBaseSettleDuration)
+      ..addStatusListener((PerformanceStatus status) {
+        if (status == PerformanceStatus.dismissed)
           config.navigator.pop();
       });
     _open();
   }
 
-  AnimationPerformance _performance;
+  Performance _performance;
 
   Widget build(BuildContext context) {
     Widget mask = new GestureDetector(
@@ -138,7 +138,7 @@ class DrawerRoute extends Route {
 
   bool get opaque => false;
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) {
     return new Focus(
       key: new GlobalObjectKey(this),
       autofocus: true,
diff --git a/packages/flutter/lib/src/widgets/ink_well.dart b/packages/flutter/lib/src/widgets/ink_well.dart
index a0f36726d1..9abe7745da 100644
--- a/packages/flutter/lib/src/widgets/ink_well.dart
+++ b/packages/flutter/lib/src/widgets/ink_well.dart
@@ -32,7 +32,7 @@ class InkSplash {
     _radius = new AnimatedValue<double>(
         _kSplashInitialSize, end: _targetRadius, curve: easeOut);
 
-    _performance = new ValueAnimation<double>(
+    _performance = new ValuePerformance<double>(
       variable: _radius,
       duration: new Duration(milliseconds: (_targetRadius / _kSplashUnconfirmedVelocity).floor())
     )..addListener(_handleRadiusChange);
@@ -47,7 +47,7 @@ class InkSplash {
   double _targetRadius;
   double _pinnedRadius;
   AnimatedValue<double> _radius;
-  AnimationPerformance _performance;
+  Performance _performance;
   Timer _startTimer;
 
   bool _cancelStartTimer() {
diff --git a/packages/flutter/lib/src/widgets/navigator.dart b/packages/flutter/lib/src/widgets/navigator.dart
index 55abf1be2c..7df0d8fe0a 100644
--- a/packages/flutter/lib/src/widgets/navigator.dart
+++ b/packages/flutter/lib/src/widgets/navigator.dart
@@ -118,7 +118,7 @@ class NavigatorState extends State<Navigator> {
   Widget build(BuildContext context) {
     List<Widget> visibleRoutes = new List<Widget>();
     bool alreadyInsertModalBarrier = false;
-    WatchableAnimationPerformance nextPerformance;
+    PerformanceView nextPerformance;
     for (int i = _history.length-1; i >= 0; i -= 1) {
       Route route = _history[i];
       if (!route.hasContent) {
@@ -126,7 +126,7 @@ class NavigatorState extends State<Navigator> {
         continue;
       }
       route.ensurePerformance(
-        direction: (i <= _currentPosition) ? Direction.forward : Direction.reverse
+        direction: (i <= _currentPosition) ? AnimationDirection.forward : AnimationDirection.reverse
       );
       route._onDismissed = () {
         setState(() {
@@ -159,28 +159,28 @@ class NavigatorState extends State<Navigator> {
 
 abstract class Route {
 
-  WatchableAnimationPerformance get performance => _performance?.view;
-  AnimationPerformance _performance;
+  PerformanceView get performance => _performance?.view;
+  Performance _performance;
   NotificationCallback _onDismissed;
 
-  AnimationPerformance createPerformance() {
+  Performance createPerformance() {
     Duration duration = transitionDuration;
     if (duration > Duration.ZERO) {
-      return new AnimationPerformance(duration: duration)
-        ..addStatusListener((AnimationStatus status) {
-          if (status == AnimationStatus.dismissed && _onDismissed != null)
+      return new Performance(duration: duration)
+        ..addStatusListener((PerformanceStatus status) {
+          if (status == PerformanceStatus.dismissed && _onDismissed != null)
             _onDismissed();
         });
     }
     return null;
   }
 
-  void ensurePerformance({ Direction direction }) {
+  void ensurePerformance({ AnimationDirection direction }) {
     assert(direction != null);
     if (_performance == null)
       _performance = createPerformance();
     if (_performance != null) {
-      AnimationStatus desiredStatus = direction == Direction.forward ? AnimationStatus.forward : AnimationStatus.reverse;
+      PerformanceStatus desiredStatus = direction == AnimationDirection.forward ? PerformanceStatus.forward : PerformanceStatus.reverse;
       if (_performance.status != desiredStatus)
         _performance.play(direction);
     }
@@ -236,14 +236,14 @@ abstract class Route {
   /// cover the entire application surface or are in any way semi-transparent.
   bool get opaque => false;
 
-  /// If this is set to a non-zero [Duration], then an [AnimationPerformance]
+  /// If this is set to a non-zero [Duration], then an [Performance]
   /// object, available via the performance field, will be created when the
   /// route is first built, using the duration described here.
   Duration get transitionDuration => Duration.ZERO;
 
   bool get isActuallyOpaque => (performance == null || _performance.isCompleted) && opaque;
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance);
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance);
   void didPop([dynamic result]) {
     if (performance == null && _onDismissed != null)
       _onDismissed();
@@ -263,7 +263,7 @@ class PageRoute extends Route {
   bool get opaque => true;
   Duration get transitionDuration => _kTransitionDuration;
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) {
     // TODO(jackson): Hit testing should ignore transform
     // TODO(jackson): Block input unless content is interactive
     return new SlideTransition(
@@ -296,5 +296,5 @@ class StateRoute extends Route {
     super.didPop(result);
   }
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) => null;
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) => null;
 }
diff --git a/packages/flutter/lib/src/widgets/popup_menu.dart b/packages/flutter/lib/src/widgets/popup_menu.dart
index c06e9539c8..3812fb779a 100644
--- a/packages/flutter/lib/src/widgets/popup_menu.dart
+++ b/packages/flutter/lib/src/widgets/popup_menu.dart
@@ -44,7 +44,7 @@ class PopupMenu extends StatefulComponent {
   final List<PopupMenuItem> items;
   final int level;
   final NavigatorState navigator;
-  final WatchableAnimationPerformance performance;
+  final PerformanceView performance;
 
   PopupMenuState createState() => new PopupMenuState();
 }
@@ -159,8 +159,8 @@ class MenuRoute extends Route {
   final PopupMenuItemsBuilder builder;
   final int level;
 
-  AnimationPerformance createPerformance() {
-    AnimationPerformance result = super.createPerformance();
+  Performance createPerformance() {
+    Performance result = super.createPerformance();
     AnimationTiming timing = new AnimationTiming();
     timing.reverseInterval = new Interval(0.0, _kMenuCloseIntervalEnd);
     result.timing = timing;
@@ -172,7 +172,7 @@ class MenuRoute extends Route {
   bool get opaque => false;
   Duration get transitionDuration => _kMenuDuration;
 
-  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
+  Widget build(NavigatorState navigator, PerformanceView nextRoutePerformance) {
     return new Positioned(
       top: position?.top,
       right: position?.right,
diff --git a/packages/flutter/lib/src/widgets/progress_indicator.dart b/packages/flutter/lib/src/widgets/progress_indicator.dart
index d6c86ef72f..c661fced9e 100644
--- a/packages/flutter/lib/src/widgets/progress_indicator.dart
+++ b/packages/flutter/lib/src/widgets/progress_indicator.dart
@@ -36,16 +36,16 @@ abstract class ProgressIndicator extends StatefulComponent {
 
 class ProgressIndicatorState extends State<ProgressIndicator> {
 
-  ValueAnimation<double> _performance;
+  ValuePerformance<double> _performance;
 
   void initState() {
     super.initState();
-    _performance = new ValueAnimation<double>(
+    _performance = new ValuePerformance<double>(
       variable: new AnimatedValue<double>(0.0, end: 1.0, curve: ease),
       duration: const Duration(milliseconds: 1500)
     );
-    _performance.addStatusListener((AnimationStatus status) {
-      if (status == AnimationStatus.completed)
+    _performance.addStatusListener((PerformanceStatus status) {
+      if (status == PerformanceStatus.completed)
         _restartAnimation();
     });
     _performance.play();
diff --git a/packages/flutter/lib/src/widgets/snack_bar.dart b/packages/flutter/lib/src/widgets/snack_bar.dart
index 179e8320ce..757d9a683a 100644
--- a/packages/flutter/lib/src/widgets/snack_bar.dart
+++ b/packages/flutter/lib/src/widgets/snack_bar.dart
@@ -49,7 +49,7 @@ class SnackBar extends AnimatedComponent {
     this.actions,
     bool showing,
     this.onDismissed
-  }) : super(key: key, direction: showing ? Direction.forward : Direction.reverse, duration: _kSlideInDuration) {
+  }) : super(key: key, direction: showing ? AnimationDirection.forward : AnimationDirection.reverse, duration: _kSlideInDuration) {
     assert(content != null);
   }
 
diff --git a/packages/flutter/lib/src/widgets/tabs.dart b/packages/flutter/lib/src/widgets/tabs.dart
index 19b9c6748b..bcee5e115e 100644
--- a/packages/flutter/lib/src/widgets/tabs.dart
+++ b/packages/flutter/lib/src/widgets/tabs.dart
@@ -408,16 +408,16 @@ class TabBar extends Scrollable {
 class TabBarState extends ScrollableState<TabBar> {
   void initState() {
     super.initState();
-    _indicatorAnimation = new ValueAnimation<Rect>()
+    _indicatorAnimation = new ValuePerformance<Rect>()
       ..duration = _kTabBarScroll
-      ..variable = new AnimatedRect(null, curve: ease);
+      ..variable = new AnimatedRectValue(null, curve: ease);
     scrollBehavior.isScrollable = config.isScrollable;
   }
 
   Size _tabBarSize;
   Size _viewportSize = Size.zero;
   List<double> _tabWidths;
-  ValueAnimation<Rect> _indicatorAnimation;
+  ValuePerformance<Rect> _indicatorAnimation;
 
   void didUpdateConfig(TabBar oldConfig) {
     super.didUpdateConfig(oldConfig);
@@ -425,7 +425,7 @@ class TabBarState extends ScrollableState<TabBar> {
       scrollTo(0.0);
   }
 
-  AnimatedRect get _indicatorRect => _indicatorAnimation.variable;
+  AnimatedRectValue get _indicatorRect => _indicatorAnimation.variable;
 
   void _startIndicatorAnimation(int fromTabIndex, int toTabIndex) {
     _indicatorRect
diff --git a/packages/flutter/lib/src/widgets/transitions.dart b/packages/flutter/lib/src/widgets/transitions.dart
index be14f5d30d..4f00c3694d 100644
--- a/packages/flutter/lib/src/widgets/transitions.dart
+++ b/packages/flutter/lib/src/widgets/transitions.dart
@@ -7,7 +7,7 @@ import 'package:sky/src/widgets/basic.dart';
 import 'package:sky/src/widgets/framework.dart';
 import 'package:vector_math/vector_math_64.dart';
 
-export 'package:sky/animation.dart' show Direction;
+export 'package:sky/animation.dart' show AnimationDirection;
 
 abstract class TransitionComponent extends StatefulComponent {
   TransitionComponent({
@@ -17,7 +17,7 @@ abstract class TransitionComponent extends StatefulComponent {
     assert(performance != null);
   }
 
-  final WatchableAnimationPerformance performance;
+  final PerformanceView performance;
 
   Widget build(BuildContext context);
 
@@ -57,7 +57,7 @@ abstract class TransitionWithChild extends TransitionComponent {
   TransitionWithChild({
     Key key,
     this.child,
-    WatchableAnimationPerformance performance
+    PerformanceView performance
   }) : super(key: key, performance: performance);
 
   final Widget child;
@@ -71,7 +71,7 @@ class SlideTransition extends TransitionWithChild {
   SlideTransition({
     Key key,
     this.position,
-    WatchableAnimationPerformance performance,
+    PerformanceView performance,
     Widget child
   }) : super(key: key,
              performance: performance,
@@ -91,7 +91,7 @@ class FadeTransition extends TransitionWithChild {
   FadeTransition({
     Key key,
     this.opacity,
-    WatchableAnimationPerformance performance,
+    PerformanceView performance,
     Widget child
   }) : super(key: key,
              performance: performance,
@@ -109,7 +109,7 @@ class ColorTransition extends TransitionWithChild {
   ColorTransition({
     Key key,
     this.color,
-    WatchableAnimationPerformance performance,
+    PerformanceView performance,
     Widget child
   }) : super(key: key,
              performance: performance,
@@ -131,7 +131,7 @@ class SquashTransition extends TransitionWithChild {
     Key key,
     this.width,
     this.height,
-    WatchableAnimationPerformance performance,
+    PerformanceView performance,
     Widget child
   }) : super(key: key,
              performance: performance,
@@ -156,7 +156,7 @@ class BuilderTransition extends TransitionComponent {
     Key key,
     this.variables,
     this.builder,
-    WatchableAnimationPerformance performance
+    PerformanceView performance
   }) : super(key: key,
              performance: performance);