[gin] Introduce Wrappable::GetObjectTemplate

mojo/apps/js/bindings/waiting_callback.h

 // Copyright 2013 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.
 
 #ifndef MOJO_APPS_JS_BINDINGS_WAITING_CALLBACK_H_
 #define MOJO_APPS_JS_BINDINGS_WAITING_CALLBACK_H_
 
 #include "gin/handle.h"
 #include "gin/runner.h"
 #include "gin/wrappable.h"
 #include "mojo/public/bindings/lib/bindings_support.h"
 
 namespace mojo {
 namespace js {
 
 class WaitingCallback : public gin::Wrappable<WaitingCallback>,
                         public BindingsSupport::AsyncWaitCallback {
  public:
   static gin::WrapperInfo kWrapperInfo;
 
   static gin::Handle<WaitingCallback> Create(
       v8::Isolate* isolate, v8::Handle<v8::Function> callback);
 
-  static void EnsureRegistered(v8::Isolate* isolate);
-
   BindingsSupport::AsyncWaitID wait_id() const {
     return wait_id_;
   }
 
   void set_wait_id(BindingsSupport::AsyncWaitID wait_id) {
     wait_id_ = wait_id;
   }
 
  private:
+  friend class gin::Wrappable<WaitingCallback>;
+  static v8::Local<v8::ObjectTemplate> GetObjectTemplate(v8::Isolate* isolate);
+
   WaitingCallback(v8::Isolate* isolate, v8::Handle<v8::Function> callback);
   virtual ~WaitingCallback();
 
   virtual void OnHandleReady(MojoResult result) OVERRIDE;
 
   base::WeakPtr<gin::Runner> runner_;
   BindingsSupport::AsyncWaitID wait_id_;
 
   DISALLOW_COPY_AND_ASSIGN(WaitingCallback);
 };
 
 }  // namespace js
 }  // namespace mojo
 
 #endif  // MOJO_APPS_JS_BINDINGS_WAITING_CALLBACK_H_