Oilpan: fix build after r369477.

third_party/WebKit/Source/platform/scroll/Scrollbar.h

 /*
  * Copyright (C) 2004, 2006 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 175 matching lines @@
     void startTimerIfNeeded(double delay);
     void stopTimerIfNeeded();
     void autoscrollPressedPart(double delay);
     ScrollDirectionPhysical pressedPartScrollDirectionPhysical();
     ScrollGranularity pressedPartScrollGranularity();
 
     RawPtrWillBeMember<ScrollableArea> m_scrollableArea;
     ScrollbarOrientation m_orientation;
     ScrollbarControlSize m_controlSize;
     ScrollbarTheme& m_theme;
-    HostWindow* m_hostWindow;
+    RawPtrWillBeMember<HostWindow> m_hostWindow;
 
     int m_visibleSize;
     int m_totalSize;
     float m_currentPos;
     float m_dragOrigin;
 
     ScrollbarPart m_hoveredPart;
     ScrollbarPart m_pressedPart;
     int m_pressedPos;
     float m_scrollPos;
@@ skipping 17 matching lines @@
 
     bool m_trackNeedsRepaint;
     bool m_thumbNeedsRepaint;
 };
 
 DEFINE_TYPE_CASTS(Scrollbar, Widget, widget, widget->isScrollbar(), widget.isScrollbar());
 
 } // namespace blink
 
 #endif // Scrollbar_h