Use auto and Range-based loop interation in Source/core/dom/custom/

Source/core/dom/custom/CustomElementUpgradeCandidateMap.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 85 matching lines @@
     elements->value->appendOrMoveToLast(element);
 }
 
 PassOwnPtrWillBeRawPtr<CustomElementUpgradeCandidateMap::ElementSet> CustomElementUpgradeCandidateMap::takeUpgradeCandidatesFor(const CustomElementDescriptor& descriptor)
 {
     OwnPtrWillBeRawPtr<ElementSet> candidates = m_unresolvedDefinitions.take(descriptor);
 
     if (!candidates)
         return nullptr;
 
-    for (ElementSet::const_iterator candidate = candidates->begin(); candidate != candidates->end(); ++candidate) {
-        unobserve(*candidate);
-        m_upgradeCandidates.remove(*candidate);
+    for (const auto& candidate : *candidates) {
+        unobserve(candidate);
+        m_upgradeCandidates.remove(candidate);
     }
     return candidates.release();
 }
 
 void CustomElementUpgradeCandidateMap::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_upgradeCandidates);
     visitor->trace(m_unresolvedDefinitions);
 #endif
     CustomElementObserver::trace(visitor);
 }
 
 }