Rip out Settings::fixedPositionCreatesStackingContext

Source/core/css/resolver/StyleAdjuster.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 210 matching lines @@
     if (style->hasAutoZIndex() && ((e && e->document().documentElement() == e)
         || style->opacity() < 1.0f
         || style->hasTransformRelatedProperty()
         || style->hasMask()
         || style->clipPath()
         || style->boxReflect()
         || style->hasFilter()
         || style->hasBlendMode()
         || style->hasIsolation()
         || style->position() == StickyPosition
-        || (style->position() == FixedPosition && e && e->document().settings() && e->document().settings()->fixedPositionCreatesStackingContext())
+        || style->position() == FixedPosition
         || isInTopLayer(e, style)
         || hasWillChangeThatCreatesStackingContext(style, e)
         ))
         style->setZIndex(0);
 
     // will-change:transform should result in the same rendering behavior as having a transform,
     // including the creation of a containing block for fixed position descendants.
     if (!style->hasTransform() && style->willChangeProperties().contains(CSSPropertyWebkitTransform)) {
         bool makeIdentity = true;
         style->setTransform(TransformOperations(makeIdentity));
@@ skipping 197 matching lines @@
     if (style->writingMode() != TopToBottomWritingMode && (style->display() == BOX || style->display() == INLINE_BOX))
         style->setWritingMode(TopToBottomWritingMode);
 
     if (isDisplayFlexibleBox(parentStyle->display()) || isDisplayGridBox(parentStyle->display())) {
         style->setFloating(NoFloat);
         style->setDisplay(equivalentBlockDisplay(style->display(), style->isFloating(), !m_useQuirksModeStyles));
     }
 }
 
 }