Simplify watched selector handling and remove remnants of user stylesheets

Source/core/css/resolver/MatchedPropertiesCache.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 173 matching lines @@
     if (style->unique() || (style->styleType() != NOPSEUDO && parentStyle->unique()))
         return false;
     if (style->hasAppearance())
         return false;
     if (style->zoom() != RenderStyle::initialZoom())
         return false;
     if (style->writingMode() != RenderStyle::initialWritingMode())
         return false;
     if (style->hasCurrentColor())
         return false;
-    // CSSPropertyInternalCallback sets the rule's selector name into the RenderStyle, and that's not recalculated if the RenderStyle is loaded from the cache, so don't cache it.
-    if (!style->callbackSelectors().isEmpty())
-        return false;
     // The cache assumes static knowledge about which properties are inherited.
     if (parentStyle->hasExplicitlyInheritedProperties())
         return false;
     return true;
 }
 
 void MatchedPropertiesCache::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_cache);
 #endif
 }
 
 }