Break dependency of AnimationPerformance on AnimatedValue

sky/sdk/lib/widgets/drawer.dart

Index: sky/sdk/lib/widgets/drawer.dart
diff --git a/sky/sdk/lib/widgets/drawer.dart b/sky/sdk/lib/widgets/drawer.dart
index ca4f9de1416844fdcffb3336f96cfabfc04bf20a..e33b8acdca5964365fa1c2e589dfe6a6a5979549 100644
--- a/sky/sdk/lib/widgets/drawer.dart
+++ b/sky/sdk/lib/widgets/drawer.dart
@@ -38,8 +38,8 @@ 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;
 
@@ -48,7 +48,7 @@ class DrawerController {
       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);
@@ -101,7 +101,7 @@ class Drawer extends AnimatedComponent {
     this.children,
     this.level: 0
   }) : super(key: key) {
-    watch(controller.performance.timeline);
+    watchPerformance(controller.performance);
   }
 
   List<Widget> children;