Break dependency of AnimationPerformance on AnimatedValue

sky/sdk/lib/widgets/drawer.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky' as sky;
 
 import '../animation/animation_performance.dart';
 import '../animation/curves.dart';
 import '../theme/shadows.dart';
 import 'animated_component.dart';
@@ skipping 20 matching lines @@
 // the user's finger. Odeon remedies this by attaching spring forces to the
 // initial timeline when animating (so it doesn't look linear).
 const Curve _kAnimationCurve = linear;
 
 typedef void DrawerStatusChangeHandler (bool showing);
 
 class DrawerController {
   DrawerController(this.onStatusChange) {
     performance = new AnimationPerformance()
       ..duration = new Duration(milliseconds: _kBaseSettleDurationMS)
-      ..variable = position;
-    performance.timeline.onValueChanged.listen(_checkValue);
+      ..variable = position
+      ..addListener(_checkValue);
   }
   final DrawerStatusChangeHandler onStatusChange;
 
   AnimationPerformance performance;
   final AnimatedPosition position = new AnimatedPosition(
       new Point(-_kWidth, 0.0), Point.origin, curve: _kAnimationCurve);
 
   bool _oldClosedState = true;
-  void _checkValue(_) {
+  void _checkValue() {
     var newClosedState = isClosed;
     if (onStatusChange != null && _oldClosedState != newClosedState) {
       onStatusChange(!newClosedState);
       _oldClosedState = newClosedState;
     }
   }
 
   bool get isClosed => performance.isDismissed;
   bool get _isMostlyClosed => position.value.x <= -_kWidth/2;
 
@@ skipping 32 matching lines @@
   }
 }
 
 class Drawer extends AnimatedComponent {
   Drawer({
     String key,
     this.controller,
     this.children,
     this.level: 0
   }) : super(key: key) {
-    watch(controller.performance.timeline);
+    watchPerformance(controller.performance);
   }
 
   List<Widget> children;
   int level;
   DrawerController controller;
 
   void syncFields(Drawer source) {
     children = source.children;
     level = source.level;
     controller = source.controller;
@@ skipping 26 matching lines @@
       child: new Stack([ mask, content ]),
       onPointerDown: controller.handlePointerDown,
       onPointerMove: controller.handlePointerMove,
       onPointerUp: controller.handlePointerUp,
       onPointerCancel: controller.handlePointerCancel,
       onGestureFlingStart: controller.handleFlingStart
     );
   }
 
 }