Implement chrome.extension.connectExternal and fix various API inconsistencies.

chrome/common/render_messages_internal.h

 // Copyright (c) 2009 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.
 
 // This header is meant to be included in multiple passes, hence no traditional
 // header guard.
 // See ipc_message_macros.h for explanation of the macros and passes.
 
 #include <map>
 #include <string>
@@ skipping 1678 matching lines @@
 
   // Wraps an IPC message that's destined to the worker on the renderer->browser
   // hop.
   IPC_MESSAGE_CONTROL1(ViewHostMsg_ForwardToWorker,
                        IPC::Message /* message */)
 
   // Open a channel to all listening contexts owned by the extension with
   // the given ID.  This always returns a valid port ID which can be used for
   // sending messages.  If an error occurred, the opener will be notified
   // asynchronously.
-  IPC_SYNC_MESSAGE_CONTROL3_1(ViewHostMsg_OpenChannelToExtension,
+  IPC_SYNC_MESSAGE_CONTROL4_1(ViewHostMsg_OpenChannelToExtension,
                               int /* routing_id */,
-                              std::string /* extension_id */,
+                              std::string /* source_extension_id */,
+                              std::string /* target_extension_id */,
                               std::string /* channel_name */,
                               int /* port_id */)
 
   // Get a port handle to the given tab.  The handle can be used for sending
   // messages to the extension.
   IPC_SYNC_MESSAGE_CONTROL4_1(ViewHostMsg_OpenChannelToTab,
                               int /* routing_id */,
                               int /* tab_id */,
                               std::string /* extension_id */,
                               std::string /* channel_name */,
@@ skipping 139 matching lines @@
   IPC_MESSAGE_CONTROL2(ViewHostMsg_DatabaseGetFileAttributes,
                        FilePath /* the name of the file */,
                        int32 /* a unique message ID */)
 
   // Asks the browser process to return the size of a DB file
   IPC_MESSAGE_CONTROL2(ViewHostMsg_DatabaseGetFileSize,
                        FilePath /* the name of the file */,
                        int32 /* a unique message ID */)
 
 IPC_END_MESSAGES(ViewHost)