Never connect a port to the same frame

chrome/browser/extensions/api/messaging/message_service.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_MESSAGING_MESSAGE_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MESSAGING_MESSAGE_SERVICE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 45 matching lines @@
   // A messaging channel. Note that the opening port can be the same as the
   // receiver, if an extension background page wants to talk to its tab (for
   // example).
   struct MessageChannel;
 
   // One side of the communication handled by extensions::MessageService.
   class MessagePort {
    public:
     virtual ~MessagePort() {}
 
+    // Called right before a channel is created for this MessagePort and |port|.
+    // This allows us to ensure that the ports have no RenderFrameHost instances
+    // in common.
+    virtual void RemoveCommonFrames(const MessagePort& port);
+
+    // Check whether the given RenderFrameHost is associated with this port.
+    virtual bool HasFrame(content::RenderFrameHost* rfh) const;
+
     // Called right before a port is connected to a channel. If false, the port
     // is not used and the channel is closed.
     virtual bool IsValidPort() = 0;
 
     // Notify the port that the channel has been opened.
     virtual void DispatchOnConnect(const std::string& channel_name,
                                    scoped_ptr<base::DictionaryValue> source_tab,
                                    int source_frame_id,
                                    int guest_process_id,
                                    int guest_render_frame_routing_id,
@@ skipping 230 matching lines @@
   LazyBackgroundTaskQueue* lazy_background_task_queue_;
 
   base::WeakPtrFactory<MessageService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageService);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MESSAGING_MESSAGE_SERVICE_H_