Add an IPC channel between the NaCl loader process and the renderer.

chrome/common/render_messages.h

Index: chrome/common/render_messages.h
===================================================================
--- chrome/common/render_messages.h	(revision 133072)
+++ chrome/common/render_messages.h	(working copy)
@@ -483,11 +483,12 @@
 // A renderer sends this to the browser process when it wants to start
 // a new instance of the Native Client process. The browser will launch
 // the process and return a handle to an IMC channel.
-IPC_SYNC_MESSAGE_CONTROL2_3(ChromeViewHostMsg_LaunchNaCl,
+IPC_SYNC_MESSAGE_CONTROL2_4(ChromeViewHostMsg_LaunchNaCl,
                             GURL /* manifest_url */,
                             int /* socket count */,
                             std::vector<nacl::FileDescriptor>
                                 /* imc channel handles */,
+                            std::string /* ppapi_channel_name */,
                             base::ProcessHandle /* NaCl process handle */,
                             base::ProcessId /* NaCl process id */)