Oilpan: tidy up some inter-stack object references.

Source/core/css/resolver/FontBuilder.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google 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.
  *
@@ skipping 82 matching lines @@
     void setSize(FontDescription&, const FontDescription::Size&);
     void updateOrientation(FontDescription&, const ComputedStyle&);
     // This function fixes up the default font size if it detects that the current generic font family has changed. -dwh
     void checkForGenericFamilyChange(const FontDescription&, FontDescription&);
     void updateSpecifiedSize(FontDescription&, const ComputedStyle&);
     void updateComputedSize(FontDescription&, const ComputedStyle&);
     void updateAdjustedSize(FontDescription&, const ComputedStyle&, FontSelector*);
 
     float getComputedSizeFromSpecifiedSize(FontDescription&, float effectiveZoom, float specifiedSize);
 
-    const Document& m_document;
+    RawPtrWillBeMember<const Document> m_document;
     FontDescription m_fontDescription;
 
     enum class PropertySetFlag {
         Weight,
         Size,
         Stretch,
         Family,
         FeatureSettings,
         Script,
         Style,
@@ skipping 11 matching lines @@
 
     void set(PropertySetFlag flag) { m_flags |= (1 << unsigned(flag)); }
     bool isSet(PropertySetFlag flag) const { return m_flags & (1 << unsigned(flag)); }
 
     unsigned m_flags;
 };
 
 }
 
 #endif