Remove unused includes from various .cpp files in core/

Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 
 #include "HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/Position.h"
 #include "core/dom/Text.h"
 #include "core/editing/RenderedPosition.h"
 #include "core/editing/TextIterator.h"
 #include "core/editing/VisiblePosition.h"
-#include "core/editing/VisibleSelection.h"
 #include "core/editing/htmlediting.h"
 #include "core/platform/text/TextBoundaries.h"
 #include "core/rendering/InlineTextBox.h"
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/RenderObject.h"
 #include <wtf/unicode/Unicode.h>
 
 namespace WebCore {
 
 using namespace HTMLNames;
@@ skipping 1364 matching lines @@
 {
     return direction == LTR ? logicalStartOfLine(c) : logicalEndOfLine(c);
 }
 
 VisiblePosition rightBoundaryOfLine(const VisiblePosition& c, TextDirection direction)
 {
     return direction == LTR ? logicalEndOfLine(c) : logicalStartOfLine(c);
 }
 
 }