Phase out local storage usage in PortSync code

client/dart.js

 // 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.
 
 // Bootstrap support for Dart scripts on the page as this script.
 if (navigator.webkitStartDart) {
   if (!navigator.webkitStartDart()) {
     document.body.innerHTML = 'This build has expired.  Please download a new Dartium at http://www.dartlang.org/dartium/index.html';
   }
 } else {
@@ skipping 141 matching lines @@
     var length = values.length;
     var result = new Array(length);
     for (var i = 0; i < length; i++) {
       result[i] = deserializeHelper(values[i]);
     }
     return result;
   }
 
   window.registerPort = function(name, port) {
     var stringified = JSON.stringify(serialize(port));
-    window.localStorage['dart-port:' + name] = stringified;
+    var attrName = 'dart-port:' + name;
+    document.documentElement.setAttribute(attrName, stringified);
+    // TODO(vsm): Phase out usage of localStorage.  We're leaving it in
+    // temporarily for backwards compatibility.
+    window.localStorage[attrName] = stringified;
   };
 
   window.lookupPort = function(name) {
-    var stringified = window.localStorage['dart-port:' + name];
+    var attrName = 'dart-port:' + name;
+    var stringified = document.documentElement.getAttribute(attrName);
+    // TODO(vsm): Phase out usage of localStorage.  We're leaving it in
+    // temporarily for backwards compatibility.
+    if (!stringified) {
+      stringified = window.localStorage[attrName];
+    }
     return deserialize(JSON.parse(stringified));
   };
 
   ReceivePortSync.id = 0;
   ReceivePortSync.map = {};
 
   ReceivePortSync.dispatchCall = function(id, message) {
     // TODO(vsm): Handle and propagate exceptions.
     var deserialized = deserialize(message);
     var result = ReceivePortSync.map[id].callback(deserialized);
@@ skipping 61 matching lines @@
     var result = null;
     var listener = function (e) {
       result = JSON.parse(getPortSyncEventData(e));
     };
     window.addEventListener(source, listener, false);
     dispatchEvent(target, [source, serialized]);
     window.removeEventListener(source, listener, false);
     return deserialize(result);
   }
 })();