Adapt and reland old position sticky implementation

third_party/WebKit/Source/core/layout/LayoutBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple 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 965 matching lines @@
 
     // The logical width of the element if it never breaks any lines at all.
     //
     // See LayoutObject::maxPreferredLogicalWidth() for more details.
     LayoutUnit m_maxPreferredLogicalWidth;
 
     // Our overflow information.
     OwnPtr<OverflowModel> m_overflow;
 
 private:
+    LayoutRect frameRectForStickyPositioning() const final { return frameRect(); }
+
     OwnPtr<LayoutBoxRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBox, isBox());
 
 inline LayoutBox* LayoutBox::previousSiblingBox() const
 {
     return toLayoutBox(previousSibling());
 }
 
@@ skipping 59 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != nullptr))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // LayoutBox_h