Clean up syntax as suggested by sethladd

sky/examples/raw/simple_render_tree.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:math';
 import 'dart:sky';
 import 'package:sky/framework/layout2.dart';
 
 class RenderSolidColor extends RenderDecoratedBox {
   final double desiredHeight;
   final double desiredWidth;
   final int backgroundColor;
 
-  RenderSolidColor(int backgroundColor, { double desiredHeight: double.INFINITY,
-                                          double desiredWidth: double.INFINITY })
-      : desiredHeight = desiredHeight,
-        desiredWidth = desiredWidth,
-        backgroundColor = backgroundColor,
+  RenderSolidColor(int backgroundColor, { this.desiredHeight: double.INFINITY,
+                                          this.desiredWidth: double.INFINITY })
+      : backgroundColor = backgroundColor,
         super(new BoxDecoration(backgroundColor: backgroundColor));
 
   BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
     return new BoxDimensions.withConstraints(constraints,
                                              height: desiredHeight,
                                              width: desiredWidth);
   }
 
   void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
     width = constraints.constrainWidth(desiredWidth);
@@ skipping 69 matching lines @@
   addFlexChild(row, 0xFF0000FF, flex: 2);
 
   root.add(row);
   row.parentData.flex = 3;
 
   renderView = new RenderView(root: root);
   renderView.layout(newWidth: view.width, newHeight: view.height);
 
   view.scheduleFrame();
 }