ASSERTION FAILED: mainAxisExtent - mainAxisBorderAndPaddingExtentForChild(child) >= 0 in RenderFlex…

Source/core/rendering/RenderFrameSet.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2006, 2008 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 84 matching lines @@
     };
 
     virtual RenderObjectChildList* virtualChildren() OVERRIDE { return children(); }
     virtual const RenderObjectChildList* virtualChildren() const OVERRIDE { return children(); }
 
     virtual const char* renderName() const OVERRIDE { return "RenderFrameSet"; }
     virtual bool isFrameSet() const OVERRIDE { return true; }
 
     virtual void layout() OVERRIDE;
     virtual void paint(PaintInfo&, const LayoutPoint&) OVERRIDE;
+    virtual void computePreferredLogicalWidths() OVERRIDE;
     virtual bool isChildAllowed(RenderObject*, RenderStyle*) const OVERRIDE;
     virtual CursorDirective getCursor(const LayoutPoint&, Cursor&) const OVERRIDE;
 
     inline HTMLFrameSetElement* frameSet() const;
 
     void setIsResizing(bool);
 
     void layOutAxis(GridAxis&, const Vector<HTMLDimension>&, int availableSpace);
     void computeEdgeInfo();
     void fillFromEdgeInfo(const FrameEdgeInfo& edgeInfo, int r, int c);
@@ skipping 15 matching lines @@
 
     bool m_isResizing;
     bool m_isChildResizing;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderFrameSet, isFrameSet());
 
 } // namespace WebCore
 
 #endif // RenderFrameSet_h