Roll Observatory packages and add a roll script

browser/lib/dart.js

-// Copyright (c) 2013, 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.
-
-(function() {
-// Bootstrap support for Dart scripts on the page as this script.
-if (navigator.userAgent.indexOf('(Dart)') === -1) {
-  // TODO:
-  // - Support in-browser compilation.
-  // - Handle inline Dart scripts.
-
-  // Fall back to compiled JS. Run through all the scripts and
-  // replace them if they have a type that indicate that they source
-  // in Dart code (type="application/dart").
-  var scripts = document.getElementsByTagName("script");
-  var length = scripts.length;
-  for (var i = 0; i < length; ++i) {
-    if (scripts[i].type == "application/dart") {
-      // Remap foo.dart to foo.dart.js.
-      if (scripts[i].src && scripts[i].src != '') {
-        var script = document.createElement('script');
-        script.src = scripts[i].src.replace(/\.dart(?=\?|$)/, '.dart.js');
-        var parent = scripts[i].parentNode;
-        // TODO(vsm): Find a solution for issue 8455 that works with more
-        // than one script.
-        document.currentScript = script;
-        parent.replaceChild(script, scripts[i]);
-      }
-    }
-  }
-}
-})();