Rename Performance to Animation in a couple more places

These should be the last references to the old "performance" name.

packages/flutter/lib/src/animation/animation_controller.dart

@@ -14,7 +14,7 @@ import 'listener_helpers.dart';
 import 'ticker.dart';
 
 class AnimationController extends Animation<double>
-  with EagerListenerMixin, LocalPerformanceListenersMixin, LocalPerformanceStatusListenersMixin {
+  with EagerListenerMixin, LocalAnimationListenersMixin, LocalAnimationStatusListenersMixin {
   AnimationController({
     double value,
     this.duration,

packages/flutter/lib/src/animation/animations.dart

@@ -62,7 +62,7 @@ abstract class ProxyAnimatedMixin {
 }
 
 class ProxyAnimation extends Animation<double>
-  with LazyListenerMixin, LocalPerformanceListenersMixin, LocalPerformanceStatusListenersMixin {
+  with LazyListenerMixin, LocalAnimationListenersMixin, LocalAnimationStatusListenersMixin {
   ProxyAnimation([Animation<double> animation]) {
     _parent = animation;
     if (_parent == null) {
@@ -122,7 +122,7 @@ class ProxyAnimation extends Animation<double>
 }
 
 class ReverseAnimation extends Animation<double>
-  with LazyListenerMixin, LocalPerformanceStatusListenersMixin {
+  with LazyListenerMixin, LocalAnimationStatusListenersMixin {
   ReverseAnimation(this.parent);
 
   final Animation<double> parent;
@@ -240,7 +240,7 @@ enum _TrainHoppingMode { minimize, maximize }
 /// removed, it exposes a [dispose()] method. Call this method to shut this
 /// object down.
 class TrainHoppingAnimation extends Animation<double>
-  with EagerListenerMixin, LocalPerformanceListenersMixin, LocalPerformanceStatusListenersMixin {
+  with EagerListenerMixin, LocalAnimationListenersMixin, LocalAnimationStatusListenersMixin {
   TrainHoppingAnimation(this._currentTrain, this._nextTrain, { this.onSwitchedTrain }) {
     assert(_currentTrain != null);
     if (_nextTrain != null) {

packages/flutter/lib/src/animation/listener_helpers.dart

@@ -38,7 +38,7 @@ abstract class EagerListenerMixin implements _ListenerMixin {
   void dispose();
 }
 
-abstract class LocalPerformanceListenersMixin extends _ListenerMixin {
+abstract class LocalAnimationListenersMixin extends _ListenerMixin {
   final List<VoidCallback> _listeners = <VoidCallback>[];
   void addListener(VoidCallback listener) {
     didRegisterListener();
@@ -55,7 +55,7 @@ abstract class LocalPerformanceListenersMixin extends _ListenerMixin {
   }
 }
 
-abstract class LocalPerformanceStatusListenersMixin extends _ListenerMixin {
+abstract class LocalAnimationStatusListenersMixin extends _ListenerMixin {
   final List<AnimationStatusListener> _statusListeners = <AnimationStatusListener>[];
   void addStatusListener(AnimationStatusListener listener) {
     didRegisterListener();

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

@@ -381,7 +381,7 @@ class _TabsScrollBehavior extends BoundedBehavior {
   }
 }
 
-abstract class TabBarSelectionPerformanceListener {
+abstract class TabBarSelectionAnimationListener {
   void handleStatusChange(AnimationStatus status);
   void handleProgressChange();
   void handleSelectionDeactivate();
@@ -503,28 +503,28 @@ class TabBarSelectionState<T> extends State<TabBarSelection<T>> {
       });
   }
 
-  final List<TabBarSelectionPerformanceListener> _performanceListeners = <TabBarSelectionPerformanceListener>[];
+  final List<TabBarSelectionAnimationListener> _animationListeners = <TabBarSelectionAnimationListener>[];
 
-  void registerPerformanceListener(TabBarSelectionPerformanceListener listener) {
-    _performanceListeners.add(listener);
+  void registerAnimationListener(TabBarSelectionAnimationListener listener) {
+    _animationListeners.add(listener);
     _controller
       ..addStatusListener(listener.handleStatusChange)
       ..addListener(listener.handleProgressChange);
   }
 
-  void unregisterPerformanceListener(TabBarSelectionPerformanceListener listener) {
-    _performanceListeners.remove(listener);
+  void unregisterAnimationListener(TabBarSelectionAnimationListener listener) {
+    _animationListeners.remove(listener);
     _controller
       ..removeStatusListener(listener.handleStatusChange)
       ..removeListener(listener.handleProgressChange);
   }
 
   void deactivate() {
-    for (TabBarSelectionPerformanceListener listener in _performanceListeners.toList()) {
+    for (TabBarSelectionAnimationListener listener in _animationListeners.toList()) {
       listener.handleSelectionDeactivate();
-      unregisterPerformanceListener(listener);
+      unregisterAnimationListener(listener);
     }
-    assert(_performanceListeners.isEmpty);
+    assert(_animationListeners.isEmpty);
   }
 
   Widget build(BuildContext context) {
@@ -552,15 +552,15 @@ class TabBar<T> extends Scrollable {
   _TabBarState createState() => new _TabBarState();
 }
 
-class _TabBarState<T> extends ScrollableState<TabBar<T>> implements TabBarSelectionPerformanceListener {
+class _TabBarState<T> extends ScrollableState<TabBar<T>> implements TabBarSelectionAnimationListener {
 
   TabBarSelectionState _selection;
   bool _valueIsChanging = false;
 
   void _initSelection(TabBarSelectionState<T> selection) {
-    _selection?.unregisterPerformanceListener(this);
+    _selection?.unregisterAnimationListener(this);
     _selection = selection;
-    _selection?.registerPerformanceListener(this);
+    _selection?.registerAnimationListener(this);
   }
 
   void initState() {
@@ -576,7 +576,7 @@ class _TabBarState<T> extends ScrollableState<TabBar<T>> implements TabBarSelect
   }
 
   void dispose() {
-    _selection?.unregisterPerformanceListener(this);
+    _selection?.unregisterAnimationListener(this);
     super.dispose();
   }
 
@@ -791,7 +791,7 @@ class TabBarView extends PageableList {
   _TabBarViewState createState() => new _TabBarViewState();
 }
 
-class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSelectionPerformanceListener {
+class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSelectionAnimationListener {
 
   TabBarSelectionState _selection;
   List<Widget> _items;
@@ -809,7 +809,7 @@ class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSe
   void _initSelection(TabBarSelectionState selection) {
     _selection = selection;
     if (_selection != null) {
-      _selection.registerPerformanceListener(this);
+      _selection.registerAnimationListener(this);
       _updateItemsAndScrollBehavior();
     }
   }
@@ -826,7 +826,7 @@ class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSe
   }
 
   void dispose() {
-    _selection?.unregisterPerformanceListener(this);
+    _selection?.unregisterAnimationListener(this);
     super.dispose();
   }
 
@@ -874,7 +874,7 @@ class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSe
   void handleProgressChange() {
     if (_selection == null || !_selection.valueIsChanging)
       return;
-    // The TabBar is driving the TabBarSelection performance.
+    // The TabBar is driving the TabBarSelection animation.
 
     final Animation<double> animation = _selection.animation;
 
@@ -906,7 +906,7 @@ class _TabBarViewState extends PageableListState<TabBarView> implements TabBarSe
   void dispatchOnScroll() {
     if (_selection == null || _selection.valueIsChanging)
       return;
-    // This class is driving the TabBarSelection's performance.
+    // This class is driving the TabBarSelection's animation.
 
     final AnimationController controller = _selection._controller;
 

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

@@ -175,9 +175,8 @@ class RelativeRectTween extends Tween<RelativeRect> {
 }
 
 /// Animated version of [Positioned] which takes a specific
-/// [AnimatedRelativeRectValue] and a [PerformanceView] to transition the
-/// child's position from a start position to and end position over the lifetime
-/// of the performance.
+/// [Animation<RelativeRect>] to transition the child's position from a start
+/// position to and end position over the lifetime of the animation.
 ///
 /// Only works if it's the child of a [Stack].
 class PositionedTransition extends AnimatedComponent {