[Effen] Add AnimatedComponent base class

sky/framework/components/input.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 '../editing/editable_string.dart';
 import '../editing/editable_text.dart';
 import '../editing/keyboard.dart';
 import '../fn.dart';
 import '../theme/colors.dart';
 
@@ skipping 31 matching lines @@
   bool _isAttachedToKeyboard = false;
   EditableString _editableValue;
 
   Input({Object key,
          this.placeholder,
          this.onChanged,
          this.focused})
       : super(key: key, stateful: true) {
     _editableValue = new EditableString(text: _value,
                                         onUpdated: _handleTextUpdated);
+    onDidUnmount(() {
+      if (_isAttachedToKeyboard)
+        keyboard.hide();
+    });
   }
 
   void _handleTextUpdated() {
     scheduleBuild();
     if (_value != _editableValue.text) {
       _value = _editableValue.text;
       if (onChanged != null)
         onChanged(_value);
     }
   }
 
-  void didUnmount() {
-    if (_isAttachedToKeyboard)
-      keyboard.hide();
-  }
-
   Node build() {
     if (focused && !_isAttachedToKeyboard) {
       keyboard.show(_editableValue.stub);
       _isAttachedToKeyboard = true;
     }
 
     List<Node> children = [];
 
     if (placeholder != null && _value.isEmpty) {
       children.add(new Container(
           style: _placeholderStyle,
           children: [new Text(placeholder)]
       ));
     }
 
     children.add(new EditableText(value: _editableValue, focused: focused));
 
     return new Container(
       style: _style,
       inlineStyle: focused ? _focusedInlineStyle : null,
       children: children
     );
   }
 }