Switch arguments to const Length references for performance

Source/platform/LengthSize.h

 /*
     Copyright (C) 1999 Lars Knoll (knoll@kde.org)
     Copyright (C) 2006, 2008 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,
@@ skipping 13 matching lines @@
 #include "platform/Length.h"
 
 namespace WebCore {
 
 class LengthSize {
 public:
     LengthSize()
     {
     }
 
-    LengthSize(Length width, Length height)
+    LengthSize(const Length& width, const Length& height)
         : m_width(width)
         , m_height(height)
     {
     }
 
     bool operator==(const LengthSize& o) const
     {
         return m_width == o.m_width && m_height == o.m_height;
     }
 
-    void setWidth(Length width) { m_width = width; }
-    Length width() const { return m_width; }
+    void setWidth(const Length& width) { m_width = width; }
+    const Length& width() const { return m_width; }
 
-    void setHeight(Length height) { m_height = height; }
-    Length height() const { return m_height; }
+    void setHeight(const Length& height) { m_height = height; }
+    const Length& height() const { return m_height; }
 
 private:
     Length m_width;
     Length m_height;
 };
 
 } // namespace WebCore
 
 #endif // LengthSize_h