Add @override annotation to known overriden methods

sky/sdk/lib/widgets/scaffold.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 '../rendering/box.dart';
 import '../rendering/object.dart';
 import '../theme/view_configuration.dart';
 import 'widget.dart';
@@ skipping 36 matching lines @@
       dropChild(old);
     if (value == null) {
       _slots.remove(slot);
     } else {
       _slots[slot] = value;
       adoptChild(value);
     }
     markNeedsLayout();
   }
 
+  @override
   void attachChildren() {
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       RenderBox box = _slots[slot];
       if (box != null)
         box.attach();
     }
   }
 
+  @override
   void detachChildren() {
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       RenderBox box = _slots[slot];
       if (box != null)
         box.detach();
     }
   }
 
   ScaffoldSlots remove(RenderBox child) {
     assert(child != null);
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       if (_slots[slot] == child) {
         this[slot] = null;
         return slot;
       }
     }
     return null;
   }
 
+  @override
   bool get sizedByParent => true;
+
+  @override
   void performResize() {
     size = constraints.biggest;
     assert(!size.isInfinite);
   }
 
   // TODO(eseidel): These change based on device size!
   // http://www.google.com/design/spec/layout/metrics-keylines.html#metrics-keylines-keylines-spacing
   static const kButtonX = 16.0; // left from right edge of body
   static const kButtonY = 16.0; // up from bottom edge of body
 
+  @override
   void performLayout() {
     double bodyHeight = size.height;
     double bodyPosition = 0.0;
     if (_slots[ScaffoldSlots.statusBar] != null) {
       RenderBox statusBar = _slots[ScaffoldSlots.statusBar];
       statusBar.layout(new BoxConstraints.tight(new Size(size.width, kStatusBarHeight)));
       assert(statusBar.parentData is BoxParentData);
       statusBar.parentData.position = new Point(0.0, size.height - kStatusBarHeight);
       bodyHeight -= kStatusBarHeight;
     }
@@ skipping 30 matching lines @@
       floatingActionButton.parentData.position = (area - floatingActionButton.size).toPoint();
     }
     if (_slots[ScaffoldSlots.drawer] != null) {
       RenderBox drawer = _slots[ScaffoldSlots.drawer];
       drawer.layout(new BoxConstraints(minWidth: 0.0, maxWidth: size.width, minHeight: size.height, maxHeight: size.height));
       assert(drawer.parentData is BoxParentData);
       drawer.parentData.position = Point.origin;
     }
   }
 
+  @override
   void paint(PaintingCanvas canvas, Offset offset) {
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       RenderBox box = _slots[slot];
       if (box != null) {
         assert(box.parentData is BoxParentData);
         canvas.paintChild(box, box.parentData.position + offset);
       }
     }
   }
 
+  @override
   void hitTestChildren(HitTestResult result, { Point position }) {
     for (ScaffoldSlots slot in ScaffoldSlots.values.reversed) {
       RenderBox box = _slots[slot];
       if (box != null) {
         assert(box.parentData is BoxParentData);
         if ((box.parentData.position & box.size).contains(position)) {
           if (box.hitTest(result, position: (position - box.parentData.position).toPoint()))
             return;
         }
       }
     }
   }
 
+  @override
   String debugDescribeChildren(String prefix) {
     return _slots.keys.map((slot) => '${prefix}${slot}: ${_slots[slot].toString(prefix)}').join();
   }
 }
 
 class Scaffold extends RenderObjectWrapper {
 
   Scaffold({
     String key,
     Widget body,
     Widget statusBar,
     Widget toolbar,
     Widget snackBar,
     Widget floatingActionButton,
     Widget drawer
   }) : super(key: key) {
     _slots[ScaffoldSlots.body] = body;
     _slots[ScaffoldSlots.statusBar] = statusBar;
     _slots[ScaffoldSlots.toolbar] = toolbar;
     _slots[ScaffoldSlots.snackBar] = snackBar;
     _slots[ScaffoldSlots.floatingActionButton] = floatingActionButton;
     _slots[ScaffoldSlots.drawer] = drawer;
   }
 
   Map<ScaffoldSlots, Widget> _slots = new Map<ScaffoldSlots, Widget>();
 
+  @override
   RenderScaffold get root => super.root;
+
+  @override
   RenderScaffold createNode() => new RenderScaffold();
 
+  @override
   void walkChildren(WidgetTreeWalker walker) {
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       Widget widget = _slots[slot];
       if (widget != null)
         walker(widget);
     }
   }
 
+  @override
   void insertChildRoot(RenderObjectWrapper child, ScaffoldSlots slot) {
     root[slot] = child != null ? child.root : null;
   }
 
+  @override
   void detachChildRoot(RenderObjectWrapper child) {
     final root = this.root; // TODO(ianh): Remove this once the analyzer is cleverer
     assert(root is RenderScaffold);
     assert(root == child.root.parent);
     root.remove(child.root);
     assert(root == this.root); // TODO(ianh): Remove this once the analyzer is cleverer
   }
 
+  @override
   void remove() {
     walkChildren((Widget child) => removeChild(child));
     super.remove();
   }
 
+  @override
   void syncRenderObject(Widget old) {
     super.syncRenderObject(old);
     for (ScaffoldSlots slot in ScaffoldSlots.values) {
       Widget widget = _slots[slot];
       _slots[slot] = syncChild(widget, old is Scaffold ? old._slots[slot] : null, slot);
       assert((_slots[slot] == null) == (widget == null));
       assert(_slots[slot] == null || _slots[slot].parent == this);
     }
   }
 
 }