Handle nested position:sticky elements

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 689 matching lines @@
   void setOverrideContainingBlockContentLogicalHeight(LayoutUnit);
   void clearContainingBlockOverrideSize();
   void clearOverrideContainingBlockContentLogicalHeight();
 
   LayoutUnit extraInlineOffset() const;
   LayoutUnit extraBlockOffset() const;
   void setExtraInlineOffset(LayoutUnit inlineOffest);
   void setExtraBlockOffset(LayoutUnit blockOffest);
   void clearExtraInlineAndBlockOffests();
 
-  LayoutSize offsetFromContainer(const LayoutObject*) const override;
+  LayoutSize offsetFromContainer(const LayoutObject*,
+                                 bool ignoreSticky = false) const override;
 
   LayoutUnit adjustBorderBoxLogicalWidthForBoxSizing(float width) const;
   LayoutUnit adjustBorderBoxLogicalHeightForBoxSizing(float height) const;
   LayoutUnit adjustContentBoxLogicalWidthForBoxSizing(float width) const;
   LayoutUnit adjustContentBoxLogicalHeightForBoxSizing(float height) const;
 
   // ComputedMarginValues holds the actual values for margins. It ignores
   // margin collapsing as they are handled in LayoutBlockFlow.
   // The margins are stored in logical coordinates (see COORDINATE
   // SYSTEMS in LayoutBoxModel) for use during layout.
@@ skipping 910 matching lines @@
 
 inline bool LayoutBox::isForcedFragmentainerBreakValue(EBreak breakValue) {
   return breakValue == BreakColumn || breakValue == BreakLeft ||
          breakValue == BreakPage || breakValue == BreakRecto ||
          breakValue == BreakRight || breakValue == BreakVerso;
 }
 
 }  // namespace blink
 
 #endif  // LayoutBox_h