Disable anchoring if ancestor changes padding or margin

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 341 matching lines @@
 
     void computeBlockPreferredLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const;
 
     bool isSelectionRoot() const;
 
 public:
     bool hasCursorCaret() const;
     bool hasDragCaret() const;
     bool hasCaret() const { return hasCursorCaret() || hasDragCaret(); }
 
+    bool heightAvailableToChildrenChanged() const { return  m_heightAvailableToChildrenChanged; }
+
 private:
     LayoutRect localCaretRect(InlineBox*, int caretOffset, LayoutUnit* extraWidthToEndOfLine = nullptr) final;
     bool isInlineBoxWrapperActuallyChild() const;
 
     Position positionForBox(InlineBox*, bool start = true) const;
 
     // End helper functions and structs used by layoutBlockChildren.
 
     void removeFromGlobalMaps();
     bool widthAvailableToChildrenHasChanged();
@@ skipping 42 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of LayoutBlock and into LayoutBlockFlow.
     friend class LayoutBlockFlow;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlock, isLayoutBlock());
 
 } // namespace blink
 
 #endif // LayoutBlock_h