Make RaisedButton support being disabled.

sky/sdk/lib/widgets/raised_button.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 '../theme2/colors.dart';
 import '../theme2/edges.dart';
 import 'basic.dart';
 import 'button_base.dart';
 import 'ink_well.dart';
 import 'material.dart';
 
 enum RaisedButtonTheme { light, dark }
 
 class RaisedButton extends ButtonBase {
 
-  RaisedButton({ Object key, this.child, this.onPressed, this.theme: RaisedButtonTheme.light }) : super(key: key);
+  RaisedButton({
+    Object key,
+    this.child,
+    this.enabled: true,
+    this.onPressed,
+    this.theme: RaisedButtonTheme.light
+  }) : super(key: key);
 
   UINode child;
-  int level;
+  bool enabled;
   Function onPressed;
   RaisedButtonTheme theme;
 
   void syncFields(RaisedButton source) {
     child = source.child;
-    level = source.level;
+    enabled = source.enabled;
     onPressed = source.onPressed;
+    theme = source.theme;
     super.syncFields(source);
   }
 
   UINode buildContent() {
+    UINode contents = new Container(
+      padding: new EdgeDims.symmetric(horizontal: 8.0),
+      child: new Center(child: child) // TODO(ianh): figure out a way to compell the child to have gray text when disabled...
+    );
     return new EventListenerNode(
       new Container(
         height: 36.0,
         constraints: new BoxConstraints(minWidth: 88.0),
         margin: new EdgeDims.all(4.0),
         child: new Material(
           edge: MaterialEdge.card,
-          child: new InkWell(
-            child: new Container(
-              padding: new EdgeDims.symmetric(horizontal: 8.0),
-              child: new Center(child: child)
-            )
-          ),
-          level: highlight ? 2 : 1,
+          child: enabled ? new InkWell(child: contents) : contents,
+          level: enabled ? (highlight ? 2 : 1) : 0,
           color: theme == RaisedButtonTheme.light

[jackson, 2015/06/16 00:16:01]

might want to work this out ahead of time for readability

-                               ? (highlight ? Grey[350] : Grey[300])
-                               : (highlight ? Blue[700] : Blue[600])
+                               ? (enabled ? (highlight ? Grey[350] : Grey[300]) : (Grey[350]))
+                               : (enabled ? (highlight ? Blue[700] : Blue[600]) : (Grey[350]))
         )
       ),
-      onGestureTap: (_) { if (onPressed != null) onPressed(); }
+      onGestureTap: (_) { if (onPressed != null && enabled) onPressed(); }
     );
   }
 
 }