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

content/browser/shared_worker/shared_worker_host.cc

 // 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.
 
 #include "content/browser/shared_worker/shared_worker_host.h"
 
 #include "base/metrics/histogram.h"
 #include "content/browser/devtools/embedded_worker_devtools_manager.h"
 #include "content/browser/frame_host/render_frame_host_delegate.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
@@ skipping 219 matching lines @@
       url, name, instance_->resource_context(), GetRenderFrameIDsForWorker());
 }
 
 void SharedWorkerHost::RelayMessage(
     const IPC::Message& message,
     SharedWorkerMessageFilter* incoming_filter) {
   if (!instance_)
     return;
   if (message.type() == WorkerMsg_Connect::ID) {
     // Crack the SharedWorker Connect message to setup routing for the port.
-    int sent_message_port_id;
-    int new_routing_id;
-    if (!WorkerMsg_Connect::Read(
-            &message, &sent_message_port_id, &new_routing_id)) {
+    WorkerMsg_Connect::Param param;
+    if (!WorkerMsg_Connect::Read(&message, &param))
       return;
-    }
+    int sent_message_port_id = param.a;
+    int new_routing_id = param.b;
+
     DCHECK(container_render_filter_);
     new_routing_id = container_render_filter_->GetNextRoutingID();
     MessagePortService::GetInstance()->UpdateMessagePort(
         sent_message_port_id,
         container_render_filter_->message_port_message_filter(),
         new_routing_id);
     SetMessagePortID(
         incoming_filter, message.routing_id(), sent_message_port_id);
     // Resend the message with the new routing id.
     Send(new WorkerMsg_Connect(
@@ skipping 64 matching lines @@
                                         int message_port_id) {
   for (FilterList::iterator i = filters_.begin(); i != filters_.end(); ++i) {
     if (i->filter() == filter && i->route_id() == route_id) {
       i->set_message_port_id(message_port_id);
       return;
     }
   }
 }
 
 }  // namespace content