Add private PPAPI interfaces for PDFium accessibility.

ppapi/proxy/ppp_pdf_proxy.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 PPAPI_PROXY_PPP_PDF_PROXY_H_
 #define PPAPI_PROXY_PPP_PDF_PROXY_H_
 
+#include <vector>
+
 #include "base/macros.h"
 #include "ppapi/c/private/ppp_pdf.h"
 #include "ppapi/proxy/interface_proxy.h"
 
 namespace ppapi {
 
 namespace proxy {
 
 class PPP_Pdf_Proxy : public InterfaceProxy {
  public:
   PPP_Pdf_Proxy(Dispatcher* dispatcher);
   virtual ~PPP_Pdf_Proxy();
 
   static const PPP_Pdf* GetProxyInterface();
 
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
  private:
   // Message handlers.
   void OnPluginMsgRotate(PP_Instance instance, bool clockwise);
   void OnPluginMsgPrintPresetOptions(PP_Instance instance,
                                      PP_PdfPrintPresetOptions_Dev* options,
                                      PP_Bool* result);
+  void OnPluginMsgEnableAccessibility(PP_Instance instance);
 
   // When this proxy is in the plugin side, this value caches the interface
   // pointer so we don't have to retrieve it from the dispatcher each time.
   // In the host, this value is always NULL.
   const PPP_Pdf* ppp_pdf_;
 
   DISALLOW_COPY_AND_ASSIGN(PPP_Pdf_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPP_PDF_PROXY_H_