Added Dartium support for JS to Dart PortSync calls

lib/dom/templates/html/dartium/impl_Window.darttemplate

Index: lib/dom/templates/html/dartium/impl_Window.darttemplate
diff --git a/lib/dom/templates/html/dartium/impl_Window.darttemplate b/lib/dom/templates/html/dartium/impl_Window.darttemplate
index 600b99e7aa65cfcaca87a88a072103c1fa880ad0..123b5908cbd16755362353aa1691c0cd06193e3e 100644
--- a/lib/dom/templates/html/dartium/impl_Window.darttemplate
+++ b/lib/dom/templates/html/dartium/impl_Window.darttemplate
@@ -15,11 +15,16 @@ class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   IDBFactory get indexedDB() => webkitIndexedDB;
 
-  // TODO(kasperl): Document this.
+  // TODO(kasperl): Document these.
   lookupPort(String name) {
     var port = JSON.parse(localStorage['dart-port:$name']);
     return _deserialize(port);
   }
 
+  registerPort(String name, var port) {
+    var serialized = _serialize(port);
+    localStorage['dart-port:$name'] = JSON.stringify(serialized);
+  }
+
 $!MEMBERS
 }