Handle nested position:sticky elements

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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 137 matching lines @@
                : relativePositionOffset().transposedSize();
   }
 
   // Populates StickyPositionConstraints, setting the sticky box rect,
   // containing block rect and updating the constraint offsets according to the
   // available space.
   FloatRect computeStickyConstrainingRect() const;
   void updateStickyPositionConstraints() const;
   LayoutSize stickyPositionOffset() const;
 
-  LayoutSize offsetForInFlowPosition() const;
+  LayoutSize offsetForInFlowPosition(bool ignoreSticky = false) const;
 
   // IE extensions. Used to calculate offsetWidth/Height. Overridden by inlines
   // (LayoutInline) to return the remaining width on a given line (and the
   // height of a single line).
   virtual LayoutUnit offsetLeft(const Element*) const;
   virtual LayoutUnit offsetTop(const Element*) const;
   virtual LayoutUnit offsetWidth() const = 0;
   virtual LayoutUnit offsetHeight() const = 0;
 
   int pixelSnappedOffsetLeft(const Element* parent) const {
@@ skipping 357 matching lines @@
   std::unique_ptr<PaintLayer> m_layer;
 
   std::unique_ptr<LayoutBoxModelObjectRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBoxModelObject, isBoxModelObject());
 
 }  // namespace blink
 
 #endif  // LayoutBoxModelObject_h