Rename watchPerformance to watch

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 13d00f1dea396958ed7d3ba6aca816dfd278ce95..150ca3f17bcf2a826eaacde3391d2347d6f3fd72 100644
--- a/sky/sdk/lib/widgets/drawer.dart
+++ b/sky/sdk/lib/widgets/drawer.dart
@@ -105,14 +105,16 @@ class Drawer extends AnimatedComponent {
     this.controller,
     this.children,
     this.level: 0
-  }) : super(key: key) {
-    watchPerformance(controller.performance);
-  }
+  }) : super(key: key);
 
   List<Widget> children;
   int level;
   DrawerController controller;
 
+  void initState() {
+    watch(controller.performance);
+  }
+
   void syncFields(Drawer source) {
     children = source.children;
     level = source.level;