Constify the rendering/ selection code

Source/core/rendering/RenderText.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 1591 matching lines @@
 
 const RenderLayerModelObject* RenderText::containerForPaintInvalidation() const
 {
     const RenderObject* rendererToIssuePaintInvalidations = containingObjectForPaintInvalidation();
     if (rendererToIssuePaintInvalidations)
         return rendererToIssuePaintInvalidations->containerForPaintInvalidation();
     // This can happen for detached render subtrees.
     return 0;
 }
 
-LayoutRect RenderText::selectionRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, bool clipToVisibleContent)
+LayoutRect RenderText::selectionRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, bool clipToVisibleContent) const
 {
     ASSERT(!needsLayout());
 
     if (selectionState() == SelectionNone)
         return LayoutRect();
     RenderBlock* cb = containingBlock();
     if (!cb)
         return LayoutRect();
 
     // Now calculate startPos and endPos for painting selection.
@@ skipping 269 matching lines @@
     }
     secureTextTimer->restartWithNewText(lastTypedCharacterOffset);
 }
 
 PassRefPtr<AbstractInlineTextBox> RenderText::firstAbstractInlineTextBox()
 {
     return AbstractInlineTextBox::getOrCreate(this, m_firstTextBox);
 }
 
 } // namespace blink