Avoid reaching for StyleResolver::m_features from StyleBuilder.

Source/core/css/resolver/StyleBuilderCustom.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * 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.
@@ skipping 1096 matching lines @@
                     // FIXME: Can a namespace be specified for an attr(foo)?
                     if (state.style()->styleType() == NOPSEUDO)
                         state.style()->setUnique();
                     else
                         state.parentStyle()->setUnique();
                     QualifiedName attr(nullAtom, contentValue->getStringValue().impl(), nullAtom);
                     const AtomicString& value = state.element()->getAttribute(attr);
                     state.style()->setContent(value.isNull() ? emptyAtom : value.impl(), didSet);
                     didSet = true;
                     // register the fact that the attribute value affects the style
-                    styleResolver->m_features.attrsInRules.add(attr.localName().impl());
+                    state.contentAttrValues().append(attr.localName());
                 } else if (contentValue->isCounter()) {
                     Counter* counterValue = contentValue->getCounterValue();
                     EListStyleType listStyleType = NoneListStyle;
                     CSSValueID listStyleIdent = counterValue->listStyleIdent();
                     if (listStyleIdent != CSSValueNone)
                         listStyleType = static_cast<EListStyleType>(listStyleIdent - CSSValueDisc);
                     OwnPtr<CounterContent> counter = adoptPtr(new CounterContent(counterValue->identifier(), listStyleType, counterValue->separator()));
                     state.style()->setContent(counter.release(), didSet);
                     didSet = true;
                 } else {
@@ skipping 995 matching lines @@
         break;
     }
     case CSSPropertyEnableBackground:
         // Silently ignoring this property for now
         // http://bugs.webkit.org/show_bug.cgi?id=6022
         break;
     }
 }
 
 } // namespace WebCore