Added impersonation of the anonymous token around CloseClipboard

ui/base/clipboard/clipboard_win.cc

 // 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.
 
 // Many of these functions are based on those found in
 // webkit/port/platform/PasteboardWin.cpp
 
 #include "ui/base/clipboard/clipboard_win.h"
 
 #include <shellapi.h>
@@ skipping 66 matching lines @@
         return true;
       }
     }
 
     // We failed to acquire the clipboard.
     return false;
   }
 
   void Release() {
     if (opened_) {
+      ::ImpersonateAnonymousToken(GetCurrentThread());
       ::CloseClipboard();
+      ::RevertToSelf();
       opened_ = false;
     } else {
       NOTREACHED();
     }
   }
 
  private:
   bool opened_;
 };
 
@@ skipping 755 matching lines @@
   if (!clipboard_owner_)
     return NULL;
 
   if (clipboard_owner_->hwnd() == NULL)
     clipboard_owner_->Create(base::Bind(&ClipboardOwnerWndProc));
 
   return clipboard_owner_->hwnd();
 }
 
 }  // namespace ui