[Sync] Add type conversion constructor for WeakHandle

chrome/browser/sync/js/js_test_util.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/js/js_test_util.h"
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_event_details.h"
@@ skipping 92 matching lines @@
   scoped_ptr<DictionaryValue> expected_details_copy(
       expected_details.DeepCopy());
   return HasDetails(JsEventDetails(expected_details_copy.get()));
 }
 
 MockJsBackend::MockJsBackend() {}
 
 MockJsBackend::~MockJsBackend() {}
 
 WeakHandle<JsBackend> MockJsBackend::AsWeakHandle() {
-  return WeakHandle<JsBackend>(AsWeakPtr());
+  return MakeWeakHandle(AsWeakPtr());
 }
 
 MockJsController::MockJsController() {}
 
 MockJsController::~MockJsController() {}
 
 MockJsEventHandler::MockJsEventHandler() {}
 
 WeakHandle<JsEventHandler> MockJsEventHandler::AsWeakHandle() {
-  return WeakHandle<JsEventHandler>(AsWeakPtr());
+  return MakeWeakHandle(AsWeakPtr());
 }
 
 MockJsEventHandler::~MockJsEventHandler() {}
 
 MockJsReplyHandler::MockJsReplyHandler() {}
 
 MockJsReplyHandler::~MockJsReplyHandler() {}
 
 WeakHandle<JsReplyHandler> MockJsReplyHandler::AsWeakHandle() {
-  return WeakHandle<JsReplyHandler>(AsWeakPtr());
+  return MakeWeakHandle(AsWeakPtr());
 }
 
 }  // namespace browser_sync