Cleanup LayoutTextControl and its subclasses.

Source/core/layout/LayoutTextControlSingleLine.cpp

 /**
  * Copyright (C) 2006, 2007, 2010 Apple Inc. All rights reserved.
  *           (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * 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.
@@ skipping 279 matching lines @@
 LayoutRect LayoutTextControlSingleLine::controlClipRect(const LayoutPoint& additionalOffset) const
 {
     ASSERT(hasControlClip());
     LayoutRect clipRect = contentBoxRect();
     if (containerElement()->layoutBox())
         clipRect = unionRect(clipRect, containerElement()->layoutBox()->frameRect());
     clipRect.moveBy(additionalOffset);
     return clipRect;
 }
 
-float LayoutTextControlSingleLine::getAvgCharWidth(AtomicString family)
+float LayoutTextControlSingleLine::getAvgCharWidth(const AtomicString& family) const
 {
     // Since Lucida Grande is the default font, we want this to match the width
     // of MS Shell Dlg, the default font for textareas in Firefox, Safari Win and
     // IE for some encodings (in IE, the default font is encoding specific).
     // 901 is the avgCharWidth value in the OS/2 table for MS Shell Dlg.
     if (family == "Lucida Grande")
         return scaleEmToUnits(901);
 
     return LayoutTextControl::getAvgCharWidth(family);
 }
@@ skipping 134 matching lines @@
     if (innerEditorElement())
         innerEditorElement()->setScrollTop(newTop);
 }
 
 HTMLInputElement* LayoutTextControlSingleLine::inputElement() const
 {
     return toHTMLInputElement(node());
 }
 
 }