Get rid of useless calls to AtomicString::impl()

Source/core/css/SelectorCheckerFastPath.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 57 matching lines @@
             element = topChildOrSubselectorMatchElement->parentElement();
             topChildOrSubselector = 0;
             return true;
         }
     }
     return false;
 }
 
 inline bool checkClassValue(const Element& element, const CSSSelector* selector)
 {
-    return element.hasClass() && element.classNames().contains(selector->value().impl());
+    return element.hasClass() && element.classNames().contains(selector->value());
 }
 
 inline bool checkIDValue(const Element& element, const CSSSelector* selector)
 {
-    return element.hasID() && element.idForStyleResolution().impl() == selector->value().impl();
+    return element.hasID() && element.idForStyleResolution() == selector->value();
 }
 
 inline bool checkExactAttributeValue(const Element& element, const CSSSelector* selector)
 {
     return SelectorChecker::checkExactAttribute(element, selector->attribute(), selector->value().impl());
 }
 
 inline bool checkTagValue(const Element& element, const CSSSelector* selector)
 {
     return SelectorChecker::tagMatches(element, selector->tagQName());
@@ skipping 121 matching lines @@
     case CSSSelector::PseudoFocus:
         return SelectorChecker::matchesFocusPseudoClass(m_element);
     default:
         ASSERT_NOT_REACHED();
     }
     return true;
 }
 
 
 }