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

content/common/resource_messages.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.
 
 // IPC messages for resource loading.
 //
 // NOTE: All messages must send an |int request_id| as their first parameter.
 
 // Multiply-included message file, hence no include guard.
 #include "base/memory/shared_memory.h"
@@ skipping 284 matching lines @@
                      int /* encoded_data_length */)
 
 // Sent when the request has been completed.
 IPC_MESSAGE_CONTROL2(ResourceMsg_RequestComplete,
                      int /* request_id */,
                      ResourceMsg_RequestCompleteData)
 
 // Resource messages sent from the renderer to the browser.
 
 // Makes a resource request via the browser.
-IPC_MESSAGE_ROUTED2(ResourceHostMsg_RequestResource,
+IPC_MESSAGE_CONTROL3(ResourceHostMsg_RequestResource,
+                    int /* routing_id */,
                     int /* request_id */,
                     ResourceHostMsg_Request)
 
 // Cancels a resource request with the ID given as the parameter.
 IPC_MESSAGE_CONTROL1(ResourceHostMsg_CancelRequest,
                      int /* request_id */)
 
 // Follows a redirect that occured for the resource request with the ID given
 // as the parameter.
 IPC_MESSAGE_CONTROL3(ResourceHostMsg_FollowRedirect,
@@ skipping 23 matching lines @@
 
 // Sent when the renderer process deletes a resource loader.
 IPC_MESSAGE_CONTROL1(ResourceHostMsg_ReleaseDownloadedFile,
                      int /* request_id */)
 
 // Sent by the renderer when a resource request changes priority.
 IPC_MESSAGE_CONTROL3(ResourceHostMsg_DidChangePriority,
                      int /* request_id */,
                      net::RequestPriority,
                      int /* intra_priority_value */)