Rename context2d to context2D.

samples/solar/web/solar.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * A solar system visualization.
  */
 
 library solar;
 
@@ skipping 102 matching lines @@
 
   void draw(num _) {
     num time = new DateTime.now().millisecondsSinceEpoch;
 
     if (renderTime != null) {
       showFps((1000 / (time - renderTime)).round());
     }
 
     renderTime = time;
 
-    var context = canvas.context2d;
+    var context = canvas.context2D;
 
     drawBackground(context);
     drawPlanets(context);
 
     requestRedraw();
   }
 
   void drawBackground(CanvasRenderingContext2D context) {
     context.clearRect(0, 0, width, height);
   }
@@ skipping 127 matching lines @@
     } else {
       num angle = solarSystem.renderTime * orbitSpeed;
 
       return new Point(
         orbitRadius * cos(angle) + x,
         orbitRadius * sin(angle) + y);
     }
   }
 
 }