Handle nested position:sticky elements

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1987 matching lines @@
   // container for fixed descendants, and may itself also be fixed position. So
   // propagate 'fixed' up only if this box is fixed position.
   if (style()->canContainFixedPositionObjects() && !isFixedPos)
     mode &= ~IsFixed;
   else if (isFixedPos)
     mode |= IsFixed;
 
   LayoutBoxModelObject::mapAncestorToLocal(ancestor, transformState, mode);
 }
 
-LayoutSize LayoutBox::offsetFromContainer(const LayoutObject* o) const {
+LayoutSize LayoutBox::offsetFromContainer(const LayoutObject* o,
+                                          bool ignoreSticky) const {
   ASSERT(o == container());
 
   LayoutSize offset;
   if (isInFlowPositioned())
-    offset += offsetForInFlowPosition();
+    offset += offsetForInFlowPosition(ignoreSticky);
 
   offset += physicalLocationOffset();
 
   if (o->hasOverflowClip())
     offset -= toLayoutBox(o)->scrolledContentOffset();
 
   if (style()->position() == AbsolutePosition && o->isInFlowPositioned() &&
       o->isLayoutInline())
     offset += toLayoutInline(o)->offsetForInFlowPositionedInline(*this);
 
@@ skipping 3670 matching lines @@
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 bool LayoutBox::shouldClipOverflow() const {
   return hasOverflowClip() || styleRef().containsPaint() || hasControlClip();
 }
 
 }  // namespace blink