Support for anonymous state routes

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 'package:sky/animation/animation_performance.dart';
 import 'package:sky/animation/curves.dart';
 import 'package:sky/theme/shadows.dart';
 import 'package:sky/widgets/animated_component.dart';
@@ skipping 54 matching lines @@
 
   void initState() {
     _builder = new AnimationBuilder()
       ..position = new AnimatedType<Point>(
           new Point(-_kWidth, 0.0), end: Point.origin, curve: _kAnimationCurve);
     _performance = _builder.createPerformance([_builder.position],
                                                 duration: _kBaseSettleDuration)
         ..addListener(_checkForStateChanged);
     watch(_performance);
     if (showing)
-      _performance.play();
+      _show();
+  }
+
+  void _show() {
+    if (navigator != null)
+      navigator.pushState(this, (_) => _performance.reverse());
+    _performance.play();
   }
 
   void syncFields(Drawer source) {
-    const String kDrawerRouteName = "[open drawer]";
     children = source.children;
     level = source.level;
     navigator = source.navigator;
     if (showing != source.showing) {
       showing = source.showing;
       if (showing) {
-        if (navigator != null) {
-          navigator.pushState(kDrawerRouteName, (_) {
-            onStatusChanged(DrawerStatus.inactive);
-          });
-        }
-        _performance.play();
+        _show();
       } else {
-        if (navigator != null && navigator.currentRoute.name == kDrawerRouteName)
-          navigator.pop();
         _performance.reverse();
       }
     }
     onStatusChanged = source.onStatusChanged;
     super.syncFields(source);
   }
 
   // TODO(mpcomplete): the animation system should handle building, maybe? Or
   // at least setting the transform. Figure out how this could work for things
   // like fades, slides, rotates, pinch, etc.
@@ skipping 24 matching lines @@
       onPointerCancel: handlePointerCancel,
       onGestureFlingStart: handleFlingStart
     );
   }
 
   double get xPosition => _builder.position.value.x;
 
   DrawerStatus _lastStatus;
   void _checkForStateChanged() {
     DrawerStatus status = _status;
-    if (_lastStatus != null && status != _lastStatus && onStatusChanged != null)
-      onStatusChanged(status);
+    if (_lastStatus != null && status != _lastStatus) {
+      if (status == DrawerStatus.inactive &&
+          navigator != null && 
+          navigator.currentRoute.key == this)
+        navigator.pop();
+      if (onStatusChanged != null)
+        onStatusChanged(status);
+    }
     _lastStatus = status;
   }
 
   DrawerStatus get _status => _performance.isDismissed ? DrawerStatus.inactive : DrawerStatus.active;
   bool get _isMostlyClosed => xPosition <= -_kWidth/2;
 
   void _settle() => _isMostlyClosed ? _performance.reverse() : _performance.play();
 
   void handleMaskTap(_) => _performance.reverse();
 
@@ skipping 16 matching lines @@
     if (!_performance.isAnimating)
       _settle();
   }
 
   void handleFlingStart(event) {
     double velocityX = event.velocityX / 1000;
     if (velocityX.abs() >= _kMinFlingVelocity)
       _performance.fling(velocity: velocityX / _kWidth);
   }
 }