Cleaned up OpenGLUI samples and added Blasteroids.

samples/openglui/src/gl.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.
 
 /**
  * An HTML-based prototype implementation for GL.
  */
 
 // TODO(vsm): Move this out of the common directory.
 library gl_html;
 
-import 'dart:html';
+import 'dart:html' as html;
 export 'dart:html' show WebGLRenderingContext;
 export 'dart:html' show Float32Array;
 export 'dart:html' show ImageElement;
 export 'dart:html' show CanvasElement;
+export 'dart:html' show AudioElement;
+export 'dart:html' show KeyboardEvent;
+export 'dart:html' show MouseEvent;
+export 'dart:html' show HtmlDocument;
+export 'dart:html' show CanvasRenderingContext2D;
+export 'dart:html' show Rect;
+
+get document => html.document;
+get window => html.window;
+get sfx_extension => 'mp3';
 
 log(message) => window.console.log(message);
+glSwapBuffers() {}
 
 getDisplayCanvas(resize) {
-  final canvas = new CanvasElement(width: window.innerWidth, height: window.innerHeight);
-  document.body.nodes.add(canvas);
-
-  window.onResize.listen((e) {
-    canvas.width = window.innerWidth;
-    canvas.height = window.innerHeight;
-    resize(canvas.width, canvas.height);
-  });
+  var canvas = document.query('#canvas');
+  if (canvas == null) {
+    canvas = new html.CanvasElement(
+        width: window.innerWidth, height: window.innerHeight);
+    document.body.nodes.add(canvas);
+  }
   return canvas;
 }
 
-animate(draw) {
-  var render;
-  render = (n) {
-    draw();
-    window.requestAnimationFrame(render);
-  };
-  render(0);
-}