Implement spawnDomUri.

tools/dom/src/native_DOMPublic.dart

 // Copyright (c) 2011, 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.
 
 part of html;
 
-// This API is exploratory.
-Future<SendPort> spawnDomFunction(Function topLevelFunction) {
+_makeSendPortFuture(spawnRequest) {
   final completer = new Completer<SendPort>();
   final port = new ReceivePort();
   port.receive((result, _) {
     completer.complete(result);
     port.close();
   });
   // TODO: SendPort.hashCode is ugly way to access port id.
-  _Utils.spawnDomFunction(topLevelFunction, port.toSendPort().hashCode);
+  spawnRequest(port.toSendPort().hashCode);
   return completer.future;
 }
 
+// This API is exploratory.
+Future<SendPort> spawnDomFunction(Function f) =>
+    _makeSendPortFuture((portId) { _Utils.spawnDomFunction(f, portId); });
+
+Future<SendPort> spawnDomUri(String uri) =>
+    _makeSendPortFuture((portId) { _Utils.spawnDomUri(uri, portId); });
+
 // testRunner implementation.
 // FIXME: provide a separate lib for testRunner.
 
 var _testRunner;
 
 TestRunner get testRunner {
   if (_testRunner == null)
     _testRunner = new TestRunner._(_NPObject.retrieve("testRunner"));
   return _testRunner;
 }
 
 class TestRunner {
   final _NPObject _npObject;
 
   TestRunner._(this._npObject);
 
   display() => _npObject.invoke('display');
   dumpAsText() => _npObject.invoke('dumpAsText');
   notifyDone() => _npObject.invoke('notifyDone');
   setCanOpenWindows() => _npObject.invoke('setCanOpenWindows');
   waitUntilDone() => _npObject.invoke('waitUntilDone');
 }