[SVG Fonts] Fix <font-face> element leak document

Source/core/svg/SVGFontFaceSource.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #if ENABLE(SVG_FONTS)
 #include "core/svg/SVGFontFaceSource.h"
 
 #include "core/svg/SVGFontData.h"
 #include "core/svg/SVGFontFaceElement.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/SimpleFontData.h"
 
 namespace WebCore {
 
-SVGFontFaceSource::SVGFontFaceSource(PassRefPtr<SVGFontFaceElement> element)
+SVGFontFaceSource::SVGFontFaceSource(SVGFontFaceElement* element)
     : m_svgFontFaceElement(element)
 {
 }
 
 PassRefPtr<SimpleFontData> SVGFontFaceSource::createFontData(const FontDescription& fontDescription)
 {
     return SimpleFontData::create(
-        SVGFontData::create(m_svgFontFaceElement.get()),
+        SVGFontData::create(m_svgFontFaceElement),
         fontDescription.effectiveFontSize(),
         fontDescription.isSyntheticBold(),
         fontDescription.isSyntheticItalic());
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(SVG_FONTS)