content: Cleanup class/struct forward declarations

content/test/test_render_view_host_factory.h

 // Copyright (c) 2012 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 CONTENT_TEST_TEST_RENDER_VIEW_HOST_FACTORY_H_
 #define CONTENT_TEST_TEST_RENDER_VIEW_HOST_FACTORY_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 
 namespace content {
 
 class SiteInstance;
 class RenderViewHostDelegate;
 class RenderProcessHostFactory;
-class SessionStorageNamespace;
 
 // Manages creation of the RenderViewHosts using our special subclass. This
 // automatically registers itself when it goes in scope, and unregisters itself
 // when it goes out of scope. Since you can't have more than one factory
 // registered at a time, you can only have one of these objects at a time.
 class TestRenderViewHostFactory : public RenderViewHostFactory {
  public:
   explicit TestRenderViewHostFactory(RenderProcessHostFactory* rph_factory);
   ~TestRenderViewHostFactory() override;
 
   virtual void set_render_process_host_factory(
       RenderProcessHostFactory* rph_factory);
   RenderViewHost* CreateRenderViewHost(
       SiteInstance* instance,
       RenderViewHostDelegate* delegate,
       RenderWidgetHostDelegate* widget_delegate,
       int32_t routing_id,
       int32_t main_frame_routing_id,
       bool swapped_out) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestRenderViewHostFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_TEST_TEST_RENDER_VIEW_HOST_FACTORY_H_