diff --git a/packages/flutter/lib/src/widgets/basic.dart b/packages/flutter/lib/src/widgets/basic.dart
index de0a0a03fd..45caafc4b4 100644
--- a/packages/flutter/lib/src/widgets/basic.dart
+++ b/packages/flutter/lib/src/widgets/basic.dart
@@ -899,6 +899,9 @@ class IgnorePointer extends OneChildRenderObjectWidget {
   }
 }
 
+
+// UTILITY NODES
+
 class MetaData extends OneChildRenderObjectWidget {
   MetaData({ Key key, Widget child, this.metaData })
     : super(key: key, child: child);
@@ -911,3 +914,12 @@ class MetaData extends OneChildRenderObjectWidget {
     renderObject.metaData = metaData;
   }
 }
+
+class KeyedSubtree extends StatelessComponent {
+  KeyedSubtree({ Key key, this.child })
+    : super(key: key);
+
+  final Widget child;
+
+  Widget build(BuildContext context) => child;
+}
\ No newline at end of file
diff --git a/packages/flutter/lib/src/widgets/dialog.dart b/packages/flutter/lib/src/widgets/dialog.dart
index 2e83515ca0..b9b24ad890 100644
--- a/packages/flutter/lib/src/widgets/dialog.dart
+++ b/packages/flutter/lib/src/widgets/dialog.dart
@@ -140,7 +140,7 @@ class DialogRoute extends Route {
 
   Duration get transitionDuration => _kTransitionDuration;
   bool get opaque => false;
-  Widget build(Key key, NavigatorState navigator) {
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance 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/drag_target.dart b/packages/flutter/lib/src/widgets/drag_target.dart
index fe600aeb8f..f5552372a0 100644
--- a/packages/flutter/lib/src/widgets/drag_target.dart
+++ b/packages/flutter/lib/src/widgets/drag_target.dart
@@ -5,6 +5,7 @@
 import 'dart:collection';
 import 'dart:sky' as sky;
 
+import 'package:sky/animation.dart';
 import 'package:sky/rendering.dart';
 import 'package:sky/src/widgets/basic.dart';
 import 'package:sky/src/widgets/binding.dart';
@@ -199,10 +200,10 @@ class DragRoute extends Route {
 
   bool get ephemeral => true;
   bool get modal => false;
-
-  Duration get transitionDuration => const Duration();
   bool get opaque => false;
-  Widget build(Key key, NavigatorState navigator) {
+  Duration get transitionDuration => const Duration();
+
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
     return new Positioned(
       left: _lastOffset.dx,
       top: _lastOffset.dy,
diff --git a/packages/flutter/lib/src/widgets/navigator.dart b/packages/flutter/lib/src/widgets/navigator.dart
index b22ef6c082..c77f365778 100644
--- a/packages/flutter/lib/src/widgets/navigator.dart
+++ b/packages/flutter/lib/src/widgets/navigator.dart
@@ -118,6 +118,7 @@ class NavigatorState extends State<Navigator> {
   Widget build(BuildContext context) {
     List<Widget> visibleRoutes = new List<Widget>();
     bool alreadyInsertModalBarrier = false;
+    WatchableAnimationPerformance nextPerformance;
     for (int i = _history.length-1; i >= 0; i -= 1) {
       Route route = _history[i];
       if (!route.hasContent) {
@@ -133,9 +134,12 @@ class NavigatorState extends State<Navigator> {
           _history.remove(route);
         });
       };
-      Key key = new ObjectKey(route);
-      Widget widget = route.build(key, this);
-      visibleRoutes.add(widget);
+      visibleRoutes.add(
+        new KeyedSubtree(
+          key: new ObjectKey(route),
+          child: route.build(this, nextPerformance)
+        )
+      );
       if (route.isActuallyOpaque)
         break;
       assert(route.modal || route.ephemeral);
@@ -146,6 +150,7 @@ class NavigatorState extends State<Navigator> {
         ));
         alreadyInsertModalBarrier = true;
       }
+      nextPerformance = route.performance;
     }
     return new Focus(child: new Stack(visibleRoutes.reversed.toList()));
   }
@@ -238,7 +243,7 @@ abstract class Route {
 
   bool get isActuallyOpaque => (performance == null || _performance.isCompleted) && opaque;
 
-  Widget build(Key key, NavigatorState navigator);
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance);
   void didPop([dynamic result]) {
     if (performance == null && _onDismissed != null)
       _onDismissed();
@@ -256,14 +261,12 @@ class PageRoute extends Route {
   final RouteBuilder builder;
 
   bool get opaque => true;
-
   Duration get transitionDuration => _kTransitionDuration;
 
-  Widget build(Key key, NavigatorState navigator) {
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
     // TODO(jackson): Hit testing should ignore transform
     // TODO(jackson): Block input unless content is interactive
     return new SlideTransition(
-      key: key,
       performance: performance,
       position: new AnimatedValue<Point>(_kTransitionStartPoint, end: Point.origin, curve: easeOut),
       child: new FadeTransition(
@@ -293,5 +296,5 @@ class RouteState extends Route {
     super.didPop(result);
   }
 
-  Widget build(Key key, NavigatorState navigator) => null;
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) => null;
 }
diff --git a/packages/flutter/lib/src/widgets/popup_menu.dart b/packages/flutter/lib/src/widgets/popup_menu.dart
index 60e02929d5..f66f1007c7 100644
--- a/packages/flutter/lib/src/widgets/popup_menu.dart
+++ b/packages/flutter/lib/src/widgets/popup_menu.dart
@@ -169,10 +169,10 @@ class MenuRoute extends Route {
 
   bool get ephemeral => false; // we could make this true, but then we'd have to use popRoute(), not pop(), in menus
   bool get modal => true;
-
-  Duration get transitionDuration => _kMenuDuration;
   bool get opaque => false;
-  Widget build(Key key, NavigatorState navigator) {
+  Duration get transitionDuration => _kMenuDuration;
+
+  Widget build(NavigatorState navigator, WatchableAnimationPerformance nextRoutePerformance) {
     return new Positioned(
       top: position?.top,
       right: position?.right,
@@ -182,7 +182,6 @@ class MenuRoute extends Route {
         key: new GlobalObjectKey(this),
         autofocus: true,
         child: new PopupMenu(
-          key: key,
           items: builder != null ? builder(navigator) : const <PopupMenuItem>[],
           level: level,
           navigator: navigator,