Add UseCounters for CSS-related *List interfaces with item() methods

Source/core/css/StyleSheetList.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/css/StyleSheetList.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/StyleEngine.h"
+#include "core/frame/UseCounter.h"
 #include "core/html/HTMLStyleElement.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 StyleSheetList::StyleSheetList(TreeScope* treeScope)
     : m_treeScope(treeScope)
 {
@@ skipping 41 matching lines @@
     // ### Bad implementation because returns a single element (are IDs always unique?)
     // and doesn't look for name attribute.
     // But unicity of stylesheet ids is good practice anyway ;)
     // FIXME: We should figure out if we should change this or fix the spec.
     Element* element = m_treeScope->getElementById(name);
     return isHTMLStyleElement(element) ? toHTMLStyleElement(element) : 0;
 }
 
 CSSStyleSheet* StyleSheetList::anonymousNamedGetter(const AtomicString& name)
 {
+    if (document())
+        UseCounter::count(*document(), UseCounter::StyleSheetListAnonymousNamedGetter);
     HTMLStyleElement* item = getNamedItem(name);
     if (!item)
         return 0;
     return item->sheet();
 }
 
 DEFINE_TRACE(StyleSheetList)
 {
     visitor->trace(m_treeScope);
 }
 
 } // namespace blink