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

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
===================================================================
--- content/browser/loader/resource_dispatcher_host_impl.cc	(revision 270218)
+++ content/browser/loader/resource_dispatcher_host_impl.cc	(working copy)
@@ -859,10 +859,10 @@
 }
 
 void ResourceDispatcherHostImpl::OnRequestResource(
-    const IPC::Message& message,
+    int routing_id,
     int request_id,
     const ResourceHostMsg_Request& request_data) {
-  BeginRequest(request_id, request_data, NULL, message.routing_id());
+  BeginRequest(request_id, request_data, NULL, routing_id);
 }
 
 // Begins a resource request with the given params on behalf of the specified