Remove the unused parts of PPB_PDF

components/pdf/common/pdf_messages.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.
 
 // Multiply-included file, no traditional include guard.
 #include <string.h>
 
 #include "content/public/common/common_param_traits.h"
 #include "content/public/common/common_param_traits_macros.h"
 #include "content/public/common/referrer.h"
 #include "ipc/ipc_message_macros.h"
 #include "url/gurl.h"
 
 #define IPC_MESSAGE_START PDFMsgStart
 
 // Updates the content restrictions, i.e. to disable print/copy.
 IPC_MESSAGE_ROUTED1(PDFHostMsg_PDFUpdateContentRestrictions,
                     int /* restrictions */)
 
 // The currently displayed PDF has an unsupported feature.
 IPC_MESSAGE_ROUTED0(PDFHostMsg_PDFHasUnsupportedFeature)
 
 // Brings up SaveAs... dialog to save specified URL.
 IPC_MESSAGE_ROUTED2(PDFHostMsg_PDFSaveURLAs,
                     GURL /* url */,
                     content::Referrer /* referrer */)
-
-// Brings up a Password... dialog for protected documents.
-IPC_SYNC_MESSAGE_ROUTED1_1(PDFHostMsg_PDFModalPromptForPassword,
-                           std::string /* prompt */,
-                           std::string /* actual_value */)