content: Cleanup class/struct forward declarations

components/guest_view/renderer/guest_view_container.h

 // Copyright 2014 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 COMPONENTS_GUEST_VIEW_RENDERER_GUEST_VIEW_CONTAINER_H_
 #define COMPONENTS_GUEST_VIEW_RENDERER_GUEST_VIEW_CONTAINER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "content/public/renderer/browser_plugin_delegate.h"
 #include "ipc/ipc_message.h"
 #include "v8/include/v8.h"
 
+namespace content {
+class RenderFrame;
+}
+
 namespace guest_view {
 
 class GuestViewRequest;
 
 class GuestViewContainer : public content::BrowserPluginDelegate {
  public:
   explicit GuestViewContainer(content::RenderFrame* render_frame);
 
   static GuestViewContainer* FromID(int element_instance_id);
 
@@ skipping 78 matching lines @@
   v8::Isolate* element_resize_isolate_;
 
   base::WeakPtrFactory<GuestViewContainer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GuestViewContainer);
 };
 
 }  // namespace guest_view
 
 #endif  // COMPONENTS_GUEST_VIEW_RENDERER_GUEST_VIEW_CONTAINER_H_