Positioned <legend> element should honor width: auto

Source/core/rendering/RenderBox.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
  * modify it under the terms of the GNU Library General Public
@@ skipping 2492 matching lines @@
 
     if (isHorizontalWritingMode() != containingBlock()->isHorizontalWritingMode())
         return true;
 
     return false;
 }
 
 bool RenderBox::autoWidthShouldFitContent() const
 {
     return node() && (node()->hasTagName(inputTag) || node()->hasTagName(selectTag) || node()->hasTagName(buttonTag)
-        || node()->hasTagName(textareaTag) || node()->hasTagName(legendTag));
+        || node()->hasTagName(textareaTag) || (node()->hasTagName(legendTag) && !style()->hasOutOfFlowPosition()));
 }
 
 void RenderBox::computeInlineDirectionMargins(RenderBlock* containingBlock, LayoutUnit containerWidth, LayoutUnit childWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd) const
 {
     const RenderStyle* containingBlockStyle = containingBlock->style();
     Length marginStartLength = style()->marginStartUsing(containingBlockStyle);
     Length marginEndLength = style()->marginEndUsing(containingBlockStyle);
 
     if (isFloating() || isInline()) {
         // Inline blocks/tables and floats don't have their margins increased.
@@ skipping 2393 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore