Switch the first thread in a child process to be the main thread...

ipc/ipc_channel_proxy.h

Index: ipc/ipc_channel_proxy.h
===================================================================
--- ipc/ipc_channel_proxy.h	(revision 21342)
+++ ipc/ipc_channel_proxy.h	(working copy)
@@ -117,6 +117,9 @@
   void AddFilter(MessageFilter* filter);
   void RemoveFilter(MessageFilter* filter);
 
+  // Called to clear the pointer to the IPC message loop when it's going away.
+  void ClearIPCMessageLoop();
+
 #if defined(OS_POSIX)
   // Calls through to the underlying channel's methods.
   // TODO(playmobil): For now this is only implemented in the case of
@@ -140,6 +143,7 @@
     Context(Channel::Listener* listener, MessageFilter* filter,
             MessageLoop* ipc_thread);
     virtual ~Context() { }
+    void ClearIPCMessageLoop() { ipc_message_loop_ = NULL; }
     MessageLoop* ipc_message_loop() const { return ipc_message_loop_; }
     const std::string& channel_id() const { return channel_id_; }