ppapi: Cleanup class/struct forward declarations

ppapi/proxy/pdf_resource.h

 // Copyright (c) 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 PPAPI_PROXY_PDF_RESOURCE_H_
 #define PPAPI_PROXY_PDF_RESOURCE_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_var.h"
 #include "ppapi/proxy/connection.h"
 #include "ppapi/proxy/plugin_resource.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 #include "ppapi/thunk/ppb_pdf_api.h"
 
 namespace ppapi {
 namespace proxy {
 
-class PluginDispatcher;
-
 class PPAPI_PROXY_EXPORT PDFResource
     : public PluginResource,
       public thunk::PPB_PDF_API {
  public:
   PDFResource(Connection connection, PP_Instance instance);
   ~PDFResource() override;
 
   // For unittesting with a given locale.
   void SetLocaleForTest(const std::string& locale) {
     locale_ = locale;
@@ skipping 35 matching lines @@
  private:
   std::string locale_;
 
   DISALLOW_COPY_AND_ASSIGN(PDFResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PDF_RESOURCE_H_