Add support for passing an arbitrary parameter to an IPC message handler. The motivation is for Web…

ipc/ipc_message.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 IPC_IPC_MESSAGE_H_
 #define IPC_IPC_MESSAGE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 123 matching lines @@
   }
 
   uint32 flags() const {
     return header()->flags;
   }
 
   // Sets all the given header values. The message should be empty at this
   // call.
   void SetHeaderValues(int32 routing, uint32 type, uint32 flags);
 
-  template<class T, class S>
-  static bool Dispatch(const Message* msg, T* obj, S* sender,
+  template<class T, class S, class P>
+  static bool Dispatch(const Message* msg, T* obj, S* sender, P* parameter,
                        void (T::*func)()) {
     (obj->*func)();
     return true;
   }
 
-  template<class T, class S>
-  static bool Dispatch(const Message* msg, T* obj, S* sender,
-                       void (T::*func)() const) {
-    (obj->*func)();
-    return true;
-  }
-
-  template<class T, class S>
-  static bool Dispatch(const Message* msg, T* obj, S* sender,
-                       void (T::*func)(const Message&)) {
-    (obj->*func)(*msg);
-    return true;
-  }
-
-  template<class T, class S>
-  static bool Dispatch(const Message* msg, T* obj, S* sender,
-                       void (T::*func)(const Message&) const) {
-    (obj->*func)(*msg);
+  template<class T, class S, class P>
+  static bool Dispatch(const Message* msg, T* obj, S* sender, P* parameter,
+                       void (T::*func)(P*)) {
+    (obj->*func)(parameter);
     return true;
   }
 
   // Used for async messages with no parameters.
   static void Log(std::string* name, const Message* msg, std::string* l) {
   }
 
   // Find the end of the message data that starts at range_start.  Returns NULL
   // if the entire message is not found in the given data range.
   static const char* FindNext(const char* range_start, const char* range_end) {
@@ skipping 107 matching lines @@
   MSG_ROUTING_NONE = -2,
 
   // indicates a general message not sent to a particular tab.
   MSG_ROUTING_CONTROL = kint32max,
 };
 
 #define IPC_REPLY_ID 0xFFFFFFF0  // Special message id for replies
 #define IPC_LOGGING_ID 0xFFFFFFF1  // Special message id for logging
 
 #endif  // IPC_IPC_MESSAGE_H_