Cleanup friends of LayoutObject

Source/core/paint/DeprecatedPaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1118 matching lines @@
     if (!m_scrollCorner && !hasScrollbar())
         return;
     if (!m_scrollCorner && hasOverlayScrollbars())
         return;
 
     LayoutObject* actualLayoutObject = layoutObjectForScrollbar(box());
     RefPtr<ComputedStyle> corner = box().hasOverflowClip() ? actualLayoutObject->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), actualLayoutObject->style()) : PassRefPtr<ComputedStyle>(nullptr);
     if (corner) {
         if (!m_scrollCorner) {
             m_scrollCorner = LayoutScrollbarPart::createAnonymous(&box().document());
-            m_scrollCorner->setParent(&box());
+            m_scrollCorner->setDangerousOneWayParent(&box());
         }
         m_scrollCorner->setStyle(corner.release());
     } else if (m_scrollCorner) {
         m_scrollCorner->destroy();
         m_scrollCorner = nullptr;
     }
 }
 
 bool DeprecatedPaintLayerScrollableArea::hitTestOverflowControls(HitTestResult& result, const IntPoint& localPoint)
 {
@@ skipping 107 matching lines @@
 void DeprecatedPaintLayerScrollableArea::updateResizerStyle()
 {
     if (!m_resizer && !box().canResize())
         return;
 
     LayoutObject* actualLayoutObject = layoutObjectForScrollbar(box());
     RefPtr<ComputedStyle> resizer = box().hasOverflowClip() ? actualLayoutObject->getUncachedPseudoStyle(PseudoStyleRequest(RESIZER), actualLayoutObject->style()) : PassRefPtr<ComputedStyle>(nullptr);
     if (resizer) {
         if (!m_resizer) {
             m_resizer = LayoutScrollbarPart::createAnonymous(&box().document());
-            m_resizer->setParent(&box());
+            m_resizer->setDangerousOneWayParent(&box());
         }
         m_resizer->setStyle(resizer.release());
     } else if (m_resizer) {
         m_resizer->destroy();
         m_resizer = nullptr;
     }
 }
 
 IntSize DeprecatedPaintLayerScrollableArea::offsetFromResizeCorner(const IntPoint& absolutePoint) const
 {
@@ skipping 193 matching lines @@
         return false;
 
     LocalFrame* frame = box().frame();
     if (!frame || !frame->isMainFrame() || !frame->settings())
         return false;
 
     return frame->settings()->viewportMetaEnabled();
 }
 
 } // namespace blink