Focus manager subclassing check

base/win_util.h

 // Copyright (c) 2006-2008 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_WIN_UTIL_H__
 #define BASE_WIN_UTIL_H__
 
 #include <windows.h>
 #include <aclapi.h>
 
@@ skipping 32 matching lines @@
 
 // Creates a security descriptor with a DACL that has one ace giving full
 // access to the current logon session.
 // The security descriptor returned must be freed using LocalFree.
 // The function returns true if it succeeds, false otherwise.
 bool GetLogonSessionOnlyDACL(SECURITY_DESCRIPTOR** security_descriptor);
 
 // Useful for subclassing a HWND.  Returns the previous window procedure.
 WNDPROC SetWindowProc(HWND hwnd, WNDPROC wndproc);
 
+// Returns true if the existing window procedure is the same as |subclass_proc|.
+bool IsSubclassed(HWND window, WNDPROC subclass_proc);
+
 // Subclasses a window, replacing its existing window procedure with the
 // specified one. Returns true if the current window procedure was replaced,
 // false if the window has already been subclassed with the specified
 // subclass procedure.
 bool Subclass(HWND window, WNDPROC subclass_proc);
 
 // Unsubclasses a window subclassed using Subclass. Returns true if
 // the window was subclassed with the specified |subclass_proc| and the window
 // was successfully unsubclassed, false if the window's window procedure is not
 // |subclass_proc|.
@@ skipping 33 matching lines @@
 // Windows's default Message Compiled resources; ignoring the inserts.
 std::wstring FormatMessage(unsigned messageid);
 
 // Uses the last Win32 error to generate a human readable message string.
 std::wstring FormatLastWin32Error();
 
 }  // namespace win_util
 
 #endif  // BASE_WIN_UTIL_H__