Use Length for baselineShiftValue in SVGLayoutStyle

Source/core/layout/style/SVGLayoutStyleDefs.h

 /*
     Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
                   2004, 2005 Rob Buis <buis@kde.org>
     Copyright (C) Research In Motion Limited 2010. All rights reserved.
 
     Based on khtml code by:
     Copyright (C) 2000-2003 Lars Knoll (knoll@kde.org)
               (C) 2000 Antti Koivisto (koivisto@kde.org)
               (C) 2000-2003 Dirk Mueller (mueller@kde.org)
               (C) 2002-2003 Apple Computer, Inc.
@@ skipping 193 matching lines @@
     bool operator==(const StyleMiscData&) const;
     bool operator!=(const StyleMiscData& other) const
     {
         return !(*this == other);
     }
 
     Color floodColor;
     float floodOpacity;
     Color lightingColor;
 
-    RefPtrWillBePersistent<SVGLength> baselineShiftValue;
+    Length baselineShiftValue;
 
 private:
     StyleMiscData();
     StyleMiscData(const StyleMiscData&);
 };
 
 // Non-inherited resources
 class StyleResourceData : public RefCounted<StyleResourceData> {
 public:
     static PassRefPtr<StyleResourceData> create() { return adoptRef(new StyleResourceData); }
@@ skipping 48 matching lines @@
         Length x;
         Length y;
     private:
         StyleLayoutData();
         StyleLayoutData(const StyleLayoutData&);
     };
 
 } // namespace blink
 
 #endif // SVGLayoutStyleDefs_h