First pass at removing position:fixed.

sky/engine/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 120 matching lines @@
     // cases where objects that should be blended as a single unit end up with a non-transparent
     // object wedged in between them. Auto z-index also becomes 0 for objects that specify transforms/masks/reflections.
     if (style->hasAutoZIndex() && ((element.document().documentElement() == element)
         || style->hasOpacity()
         || style->hasTransformRelatedProperty()
         || style->hasMask()
         || style->clipPath()
         || style->hasFilter()
         || style->hasBlendMode()
         || style->hasIsolation()
-        || style->position() == FixedPosition
         || hasWillChangeThatCreatesStackingContext(style)))
         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) || style->willChangeProperties().contains(CSSPropertyTransform))) {
         bool makeIdentity = true;
         style->setTransform(TransformOperations(makeIdentity));
     }
 
@@ skipping 98 matching lines @@
     // clear how that should work.
     if (style->display() == INLINE && style->styleType() == NOPSEUDO && style->writingMode() != parentStyle->writingMode())
         style->setDisplay(INLINE_BLOCK);
 
     if (parentStyle->isDisplayFlexibleOrGridBox()) {
         style->setDisplay(equivalentBlockDisplay(style->display()));
     }
 }
 
 }