Add support for passing an arbitrary parameter to an IPC message handler. The motivation is for Web…

chrome/renderer/pepper/pepper_flash_drm_renderer_host.cc

 // 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.
 
 #include "chrome/renderer/pepper/pepper_flash_drm_renderer_host.h"
 
 #include "base/files/file_path.h"
 #include "content/public/renderer/pepper_plugin_instance.h"
 #include "content/public/renderer/renderer_ppapi_host.h"
 #include "ppapi/c/pp_errors.h"
@@ skipping 14 matching lines @@
     PP_Resource resource)
     : ResourceHost(host->GetPpapiHost(), instance, resource),
       renderer_ppapi_host_(host),
       weak_factory_(this) {}
 
 PepperFlashDRMRendererHost::~PepperFlashDRMRendererHost() {}
 
 int32_t PepperFlashDRMRendererHost::OnResourceMessageReceived(
     const IPC::Message& msg,
     ppapi::host::HostMessageContext* context) {
-  IPC_BEGIN_MESSAGE_MAP(PepperFlashDRMRendererHost, msg)
-  PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FlashDRM_GetVoucherFile,
-                                      OnGetVoucherFile)
-  IPC_END_MESSAGE_MAP()
+  PPAPI_BEGIN_MESSAGE_MAP(PepperFlashDRMRendererHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FlashDRM_GetVoucherFile,
+                                        OnGetVoucherFile)
+  PPAPI_END_MESSAGE_MAP()
   return PP_ERROR_FAILED;
 }
 
 int32_t PepperFlashDRMRendererHost::OnGetVoucherFile(
     ppapi::host::HostMessageContext* context) {
   content::PepperPluginInstance* plugin_instance =
       renderer_ppapi_host_->GetPluginInstance(pp_instance());
   if (!plugin_instance)
     return PP_ERROR_FAILED;
 
@@ skipping 29 matching lines @@
   int browser_pending_host_id = browser_pending_host_ids[0];
 
   ppapi::FileRefCreateInfo create_info =
       ppapi::MakeExternalFileRefCreateInfo(external_path,
                                            std::string(),
                                            browser_pending_host_id,
                                            renderer_pending_host_id);
   host()->SendReply(reply_context,
                     PpapiPluginMsg_FlashDRM_GetVoucherFileReply(create_info));
 }