Provide a fallback for AudioBufferSourceNode.start to noteOn and stop to

tests/html/audiobuffersourcenode_test.dart

+#library('AudioBufferSourceNodeTest');
+#import('../../pkg/unittest/unittest.dart');
+#import('../../pkg/unittest/html_config.dart');
+#import('dart:html');
+
+main() {
+
+  useHtmlConfiguration();
+
+  test('createBuffer', () {
+      var ctx = new AudioContext();
+      AudioBufferSourceNode node = ctx.createBufferSource();

[blois, 2012/10/02 23:43:25]

I don't think this test works on all (many?) platforms- you're probably going to
need some updates to html.status.

[Emily Fortuna, 2012/10/02 23:59:43]

It works on Chrome and Safari 6, but I had forgotten to check Firefox. (and
Safari 5.2 probably isn't going to work either) Updated.

+      node.start(ctx.currentTime, 0, 2);
+      node.stop(ctx.currentTime + 2);
+      expect(node is AudioBufferSourceNode);
+  });
+}