Don't fail the style assert in Element::rendererIsFocusable if the document is active.

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 219 matching lines @@
         return canvas->renderer() && canvas->renderer()->style()->visibility() == VISIBLE;
     }
 
     // FIXME: These asserts should be in Node::isFocusable, but there are some
     // callsites like Document::setFocusedElement that would currently fail on
     // them. See crbug.com/251163
     if (!renderer()) {
         // We can't just use needsStyleRecalc() because if the node is in a
         // display:none tree it might say it needs style recalc but the whole
         // document is actually up to date.
-        ASSERT(!document().childNeedsStyleRecalc());
+        // In addition, style cannot be cleared out for non-active documents,
+        // so in that case the childNeedsStyleRecalc check is invalid.
+        ASSERT(!document().isActive() || !document().childNeedsStyleRecalc());
     }
 
     // FIXME: Even if we are not visible, we might have a child that is visible.
     // Hyatt wants to fix that some day with a "has visible content" flag or the like.
     if (!renderer() || renderer()->style()->visibility() != VISIBLE)
         return false;
 
     return true;
 }
 
@@ skipping 3011 matching lines @@
 {
 #if ENABLE(OILPAN)
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
 #endif
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink