Making sure that base::MessagePumpForUI from different modules are isolated from each other.

base/message_pump_win.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 BASE_MESSAGE_PUMP_WIN_H_
 #define BASE_MESSAGE_PUMP_WIN_H_
 #pragma once
 
 #include <windows.h>
 
@@ skipping 136 matching lines @@
       HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
   virtual void DoRunLoop();
   void InitMessageWnd();
   void WaitForWork();
   void HandleWorkMessage();
   void HandleTimerMessage();
   bool ProcessNextWindowsMessage();
   bool ProcessMessageHelper(const MSG& msg);
   bool ProcessPumpReplacementMessage();
 
+  // Instance of the module containing the window procedure.
+  HMODULE instance_;
+
   // A hidden message-only window.
   HWND message_hwnd_;
 };
 
 //-----------------------------------------------------------------------------
 // MessagePumpForIO extends MessagePumpWin with methods that are particular to a
 // MessageLoop instantiated with TYPE_IO. This version of MessagePump does not
 // deal with Windows mesagges, and instead has a Run loop based on Completion
 // Ports so it is better suited for IO operations.
 //
@@ skipping 162 matching lines @@
   // This list will be empty almost always. It stores IO completions that have
   // not been delivered yet because somebody was doing cleanup.
   std::list<IOItem> completed_io_;
 
   ObserverList<IOObserver> io_observers_;
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_WIN_H_