Cleanup LayoutTextControl and its subclasses.

Source/core/layout/LayoutTextControl.h

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 40 matching lines @@
 
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 
     void hitInnerEditorElement(HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset);
 
     int textBlockLogicalWidth() const;
     int textBlockLogicalHeight() const;
 
     float scaleEmToUnits(int x) const;
 
-    static bool hasValidAvgCharWidth(AtomicString family);
-    virtual float getAvgCharWidth(AtomicString family);
+    static bool hasValidAvgCharWidth(const AtomicString& family);
+    virtual float getAvgCharWidth(const AtomicString& family) const;
     virtual LayoutUnit preferredContentLogicalWidth(float charWidth) const = 0;
     virtual LayoutUnit computeControlLogicalHeight(LayoutUnit lineHeight, LayoutUnit nonContentHeight) const = 0;
 
     void updateFromElement() override;
     void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const override;
     LayoutObject* layoutSpecialExcludedChild(bool relayoutChildren, SubtreeLayoutScope&) override;
 
     // We need to override this function because we don't want overflow:hidden on an <input>
     // to affect the baseline calculation. This is necessary because we are an inline-block
     // element as an implementation detail which would normally be affected by this.
@@ skipping 32 matching lines @@
         return LayoutBlock::baselinePosition(baseline, firstLine, direction, position);
     }
     int firstLineBoxBaseline() const override { return LayoutBlock::firstLineBoxBaseline(); }
     int inlineBlockBaseline(LineDirectionMode direction) const override { return lastLineBoxBaseline(direction); }
 };
 
 
 } // namespace blink
 
 #endif // LayoutTextControl_h