Constify the rendering/ selection code

Source/core/rendering/InlineBox.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 264 matching lines @@
 }
 
 InlineBox* InlineBox::prevLeafChildIgnoringLineBreak() const
 {
     InlineBox* leaf = prevLeafChild();
     if (leaf && leaf->isLineBreak())
         return 0;
     return leaf;
 }
 
-RenderObject::SelectionState InlineBox::selectionState()
+RenderObject::SelectionState InlineBox::selectionState() const
 {
     return renderer().selectionState();
 }
 
 bool InlineBox::canAccommodateEllipsis(bool ltr, int blockEdge, int ellipsisWidth) const
 {
     // Non-replaced elements can always accommodate an ellipsis.
     if (!renderer().isReplaced())
         return true;
 
@@ skipping 65 matching lines @@
         b->showTreeForThis();
 }
 
 void showLineTree(const blink::InlineBox* b)
 {
     if (b)
         b->showLineTreeForThis();
 }
 
 #endif