Send port disconnect events when a frame is unloaded.

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 <string>
 #include <vector>
@@ skipping 1365 matching lines @@
                               int /* routing_id */,
                               std::string /* extension_id */,
                               int /* port_id */)
 
   // Send a message to an extension process.  The handle is the value returned
   // by ViewHostMsg_OpenChannelToExtension.
   IPC_MESSAGE_ROUTED2(ViewHostMsg_ExtensionPostMessage,
                       int /* port_id */,
                       std::string /* message */)
 
+  // Send a message to an extension process.  The handle is the value returned
+  // by ViewHostMsg_OpenChannelToExtension.
+  IPC_MESSAGE_CONTROL1(ViewHostMsg_ExtensionCloseChannel,
+                       int /* port_id */)
+
   // Message to show a popup menu using native cocoa controls (Mac only).
   IPC_MESSAGE_ROUTED1(ViewHostMsg_ShowPopup,
                       ViewHostMsg_ShowPopup_Params)
 
   // Sent as a result of a focus change in the renderer (if accessibility is
   // enabled), to notify the browser side that its accessibility focus needs to
   // change as well. Takes the id of the accessibility object that now has
   // focus.
   IPC_MESSAGE_ROUTED1(ViewHostMsg_AccessibilityFocusChange,
                       int /* accessibility object id */)
@@ skipping 33 matching lines @@
   // web resource.  |error_message| is a user-readable explanation of what
   // went wrong.
   IPC_MESSAGE_CONTROL1(UtilityHostMsg_UnpackWebResource_Failed,
                        std::string /* error_message, if any */)
 
   // Sent by the renderer process to acknowledge receipt of a
   // ViewMsg_CSSInsertRequest message and css has been inserted into the frame.
   IPC_MESSAGE_ROUTED0(ViewHostMsg_OnCSSInserted)
 
 IPC_END_MESSAGES(ViewHost)