Fix Dart analyzer warnings in scaffold.dart

sky/sdk/lib/framework/components2/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 '../fn2.dart';
 import '../theme/typography.dart' as typography;
 import 'dart:sky' as sky;
+import '../rendering/render_box.dart';
+import '../rendering/render_node.dart';
 
 // RenderNode
-class RenderScaffold extends RenderDecoratedBox {
+class RenderScaffold extends RenderBox {
 
   RenderScaffold({
-    BoxDecoration decoration,
     RenderBox toolbar,
     RenderBox body,
     RenderBox statusbar,
     RenderBox drawer,
     RenderBox floatingActionButton
-  }) : super(decoration) {
+  }) {
     this.toolbar = toolbar;
     this.body = body;
     this.statusbar = statusbar;
     this.drawer = drawer;
     this.floatingActionButton = floatingActionButton;
   }
 
   RenderBox _toolbar;
   RenderBox get toolbar => _toolbar;
   void set toolbar (RenderBox value) {
@@ skipping 83 matching lines @@
       body.parentData.position = new sky.Point(0.0, bodyPosition);
     }
     if (drawer != null) {
       drawer.layout(new BoxConstraints(minWidth: 0.0, maxWidth: size.width, minHeight: size.height, maxHeight: size.height));
       assert(drawer.parentData is BoxParentData);
       drawer.parentData.position = new sky.Point(0.0, 0.0);
     }
     if (floatingActionButton != null) {
       floatingActionButton.layout(new BoxConstraints(minWidth: 0.0, maxWidth: size.width, minHeight: size.height, maxHeight: size.height));
       assert(floatingActionButton.parentData is BoxParentData);
-      floatingActionButton.parentData.position = new sky.Point(size.width - xButtonX, bodyPosition + bodyHeight - kButtonY);
+      floatingActionButton.parentData.position = new sky.Point(size.width - kButtonX, bodyPosition + bodyHeight - kButtonY);
     }
   }
 
   void paint(RenderNodeDisplayList canvas) {
     if (body != null)
       canvas.paintChild(body, (body.parentData as BoxParentData).position);
     if (statusbar != null)
       canvas.paintChild(statusbar, (statusbar.parentData as BoxParentData).position);
     if (toolbar != null)
       canvas.paintChild(toolbar, (toolbar.parentData as BoxParentData).position);
     if (floatingActionButton != null)
       canvas.paintChild(floatingActionButton, (floatingActionButton.parentData as BoxParentData).position);
     if (drawer != null)
       canvas.paintChild(drawer, (drawer.parentData as BoxParentData).position);
   }
 
   void hitTestChildren(HitTestResult result, { sky.Point position }) {
     assert(floatingActionButton == null || floatingActionButton.parentData is BoxParentData);
     assert(statusbar == null || statusbar.parentData is BoxParentData);
-    if ((drawer != null) && (x < drawer.size.width)) {
+    if ((drawer != null) && (position.x < drawer.size.width)) {
       drawer.hitTest(result, position: position);
     } else if ((floatingActionButton != null) && (position.x >= floatingActionButton.parentData.position.x) && (position.x < floatingActionButton.parentData.position.x + floatingActionButton.size.width)
                                               && (position.y >= floatingActionButton.parentData.position.y) && (position.y < floatingActionButton.parentData.position.y + floatingActionButton.size.height)) {
       floatingActionButton.hitTest(result, position: new sky.Point(position.x - floatingActionButton.parentData.position.x, position.y - floatingActionButton.parentData.position.y));
     } else if ((toolbar != null) && (position.y < toolbar.size.height)) {
       toolbar.hitTest(result, position: position);
     } else if ((statusbar != null) && (position.y > statusbar.parentData.position.y)) {
       statusbar.hitTest(result, position: new sky.Point(position.x, position.y - statusbar.parentData.position.y));
     } else if (body != null) {
       body.hitTest(result, position: new sky.Point(position.x, position.y - body.parentData.position.y));
@@ skipping 59 matching lines @@
   void syncRenderNode(UINode old) {
     super.syncRenderNode(old);
     syncChild(toolbar, old is Scaffold ? old.toolbar : null, #toolbar);
     syncChild(body, old is Scaffold ? old.body : null, #body);
     syncChild(statusbar, old is Scaffold ? old.statusbar : null, #statusbar);
     syncChild(drawer, old is Scaffold ? old.drawer : null, #drawer);
     syncChild(floatingActionButton, old is Scaffold ? old.floatingActionButton : null, #floatingActionButton);
   }
 
 }