Use a block cursor in overtype mode

Source/core/editing/Editor.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 2339 matching lines @@
         checkingTypes |= TextCheckingTypeGrammar;
 
     return checkingTypes;
 }
 
 bool Editor::unifiedTextCheckerEnabled() const
 {
     return WebCore::unifiedTextCheckerEnabled(m_frame);
 }
 
+void Editor::toggleOverwriteModeEnabled()
+{
+    m_overwriteModeEnabled = !m_overwriteModeEnabled;
+    frame()->selection()->setShouldShowBlockCursor(m_overwriteModeEnabled);
+};
+
 } // namespace WebCore