First experimental steps towards a better story for JS interop.

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

Index: lib/dom/templates/html/frog/impl_Window.darttemplate
diff --git a/lib/dom/templates/html/frog/impl_Window.darttemplate b/lib/dom/templates/html/frog/impl_Window.darttemplate
index e97ecb66207b262dfff92a08609272ded587830d..0f076ebf774ac373bde4793b72e68d733c852b9e 100644
--- a/lib/dom/templates/html/frog/impl_Window.darttemplate
+++ b/lib/dom/templates/html/frog/impl_Window.darttemplate
@@ -118,5 +118,11 @@ class $CLASSNAME$EXTENDS$IMPLEMENTS native "@*DOMWindow" {
   _IDBFactoryImpl _get_indexedDB() native
       'return this.indexedDB || this.webkitIndexedDB || this.mozIndexedDB';
 
+  // TODO(kasperl): Document this.
+  lookupPort(String name) {
+    var port = JSON.parse(localStorage['dart-port:$name']);
+    return _deserialize(port);
+  }
+
 $!MEMBERS
 }