Move dart:dom to dart:dom_deprecated

frog/tests/canvastest.dart

 // Copyright (c) 2011, 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.
 
-#import("dart:dom");
+#import("dart:dom_deprecated");
 
 void main() {
   var element = document.createElement('div');
   element.innerHTML = "Hello from Dart!";
   document.body.appendChild(element);
 
   HTMLCanvasElement canvas = document.createElement('canvas');
   canvas.setAttribute('width', '100');
   canvas.setAttribute('height', '100');
   document.body.appendChild(canvas);
 
   var context = canvas.getContext('2d');
   context.fillRect(10, 10, 20, 20);
 }