Make sure z-index is adjusted after applying pending animations on elements

third_party/WebKit/Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1641 matching lines @@
     if (hasCustomStyleCallbacks())
         style = customStyleForLayoutObject();
     if (!style)
         style = originalStyleForLayoutObject();
     DCHECK(style);
 
     // styleForElement() might add active animations so we need to get it again.
     if (ElementAnimations* elementAnimations = this->elementAnimations()) {
         elementAnimations->cssAnimations().maybeApplyPendingUpdate(this);
         elementAnimations->updateAnimationFlags(*style);
+
+        // This is supposed to be done by StyleAdjuster, but we may not have updated animation
+        // list until this point.
+        if (style->hasAutoZIndex() && (style->hasCurrentOpacityAnimation()
+            || style->hasCurrentTransformAnimation()
+            || style->hasCurrentFilterAnimation()))
+            style->setZIndex(0);
     }
 
     if (style->hasTransform()) {
         if (const StylePropertySet* inlineStyle = this->inlineStyle())
             style->setHasInlineTransform(inlineStyle->hasProperty(CSSPropertyTransform));
     }
 
     return style.release();
 }
 
@@ skipping 2037 matching lines @@
 
 DEFINE_TRACE_WRAPPERS(Element)
 {
     if (hasRareData()) {
         visitor->traceWrappers(elementRareData());
     }
     ContainerNode::traceWrappers(visitor);
 }
 
 } // namespace blink