Example of how to interpose yourself in a message stream.

ipc/ipc_channel_proxy.cc

 // Copyright (c) 2011 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 "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_logging.h"
 #include "ipc/ipc_message_utils.h"
@@ skipping 263 matching lines @@
   if (listener_)
     listener_->OnChannelError();
 }
 
 //-----------------------------------------------------------------------------
 
 ChannelProxy::ChannelProxy(const IPC::ChannelHandle& channel_handle,
                            Channel::Mode mode,
                            Channel::Listener* listener,
                            MessageLoop* ipc_thread)
-    : context_(new Context(listener, ipc_thread)) {
+    : context_(new Context(listener, ipc_thread)),
+      outgoing_message_filter_(NULL) {
   Init(channel_handle, mode, ipc_thread, true);
 }
 
 ChannelProxy::ChannelProxy(const IPC::ChannelHandle& channel_handle,
                            Channel::Mode mode,
                            MessageLoop* ipc_thread,
                            Context* context,
                            bool create_pipe_now)
     : context_(context) {
   Init(channel_handle, mode, ipc_thread, create_pipe_now);
@@ skipping 85 matching lines @@
   Channel *channel = context_.get()->channel_.get();
   // Channel must have been created first.
   DCHECK(channel) << context_.get()->channel_id_;
   return channel->GetClientEuid(client_euid);
 }
 #endif
 
 //-----------------------------------------------------------------------------
 
 }  // namespace IPC