[Effen] Add AnimatedComponent base class

sky/framework/editing/editable_text.dart

Index: sky/framework/editing/editable_text.dart
diff --git a/sky/framework/editing/editable_text.dart b/sky/framework/editing/editable_text.dart
index 5a0b0810d10c24e941dbb125997529d067995d87..cbc429f4a02270984d82116e20a3b63351121929 100644
--- a/sky/framework/editing/editable_text.dart
+++ b/sky/framework/editing/editable_text.dart
@@ -32,6 +32,10 @@ class EditableText extends Component {
 
   EditableText({Object key, this.value, this.focused})
       : super(key: key, stateful: true) {
+    onDidUnmount(() {
+      if (_cursorTimer != null)
+        _stopCursorTimer();
+    });
   }
 
   void _cursorTick(Timer timer) {
@@ -52,11 +56,6 @@ class EditableText extends Component {
     _showCursor = false;
   }
 
-  void didUnmount() {
-    if (_cursorTimer != null)
-      _stopCursorTimer();
-  }
-
   Node build() {
     if (focused && _cursorTimer == null)
       _startCursorTimer();