Reimplement min-width: auto

Source/core/layout/LayoutMenuList.cpp

 /*
  * This file is part of the select element renderer in WebCore.
  *
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *               2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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
@@ skipping 86 matching lines @@
     m_innerBlock = createAnonymousBlock();
     adjustInnerStyle();
     LayoutFlexibleBox::addChild(m_innerBlock);
 }
 
 void LayoutMenuList::adjustInnerStyle()
 {
     ComputedStyle& innerStyle = m_innerBlock->mutableStyleRef();
     innerStyle.setFlexGrow(1);
     innerStyle.setFlexShrink(1);
+    // min-width: 0; is needed for correct shrinking.
+    innerStyle.setMinWidth(Length(0, Fixed));
     // Use margin:auto instead of align-items:center to get safe centering, i.e.
     // when the content overflows, treat it the same as align-items: flex-start.
     // But we only do that for the cases where html.css would otherwise use center.
     if (style()->alignItems() == ItemPositionCenter) {
         innerStyle.setMarginTop(Length());
         innerStyle.setMarginBottom(Length());
         innerStyle.setAlignSelf(ItemPositionFlexStart);
     }
 
     innerStyle.setPaddingLeft(Length(LayoutTheme::theme().popupInternalPaddingLeft(styleRef()), Fixed));
@@ skipping 506 matching lines @@
     HTMLElement* element = listItems[listIndex];
     return isHTMLOptionElement(*element) && toHTMLOptionElement(*element).selected();
 }
 
 void LayoutMenuList::provisionalSelectionChanged(unsigned listIndex)
 {
     setIndexToSelectOnCancel(listIndex);
 }
 
 } // namespace blink