content: Cleanup class/struct forward declarations

content/renderer/pepper/mock_renderer_ppapi_host.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_RENDERER_PEPPER_MOCK_RENDERER_PPAPI_HOST_H_
 #define CONTENT_RENDERER_PEPPER_MOCK_RENDERER_PPAPI_HOST_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "content/public/renderer/renderer_ppapi_host.h"
 #include "content/renderer/pepper/content_renderer_pepper_host_factory.h"
 #include "ppapi/host/ppapi_host.h"
 #include "ppapi/proxy/resource_message_test_sink.h"
 
 namespace content {
 class FakePepperPluginInstance;
-class PluginModule;
 
 // A mock RendererPpapiHost for testing resource hosts. Messages sent by
 // resources through this will get added to the test sink.
 class MockRendererPpapiHost : public RendererPpapiHost {
  public:
   // This function takes the RenderView and instance that the mock resource
   // host will be associated with.
   MockRendererPpapiHost(RenderView* render_view, PP_Instance instance);
   ~MockRendererPpapiHost() override;
 
@@ skipping 42 matching lines @@
   bool has_user_gesture_;
 
   std::unique_ptr<FakePepperPluginInstance> plugin_instance_;
 
   DISALLOW_COPY_AND_ASSIGN(MockRendererPpapiHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_MOCK_RENDERER_PPAPI_HOST_H_