Update from https://crrev.com/320343

base/prefs/pref_notifier_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/prefs/pref_notifier_impl.h"
 
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "base/stl_util.h"
 
 PrefNotifierImpl::PrefNotifierImpl()
     : pref_service_(NULL) {
 }
 
 PrefNotifierImpl::PrefNotifierImpl(PrefService* service)
     : pref_service_(service) {
 }
 
 PrefNotifierImpl::~PrefNotifierImpl() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Verify that there are no pref observers when we shut down.
   for (PrefObserverMap::iterator it = pref_observers_.begin();
        it != pref_observers_.end(); ++it) {
-    PrefObserverList::Iterator obs_iterator(*(it->second));
+    PrefObserverList::Iterator obs_iterator(it->second);
     if (obs_iterator.GetNext()) {
       LOG(WARNING) << "pref observer found at shutdown " << it->first;
     }
   }
 
   // Same for initialization observers.
   if (!init_observers_.empty())
     LOG(WARNING) << "Init observer found at shutdown.";
 
   STLDeleteContainerPairSecondPointers(pref_observers_.begin(),
@@ skipping 72 matching lines @@
 
   FOR_EACH_OBSERVER(PrefObserver,
                     *(observer_iterator->second),
                     OnPreferenceChanged(pref_service_, path));
 }
 
 void PrefNotifierImpl::SetPrefService(PrefService* pref_service) {
   DCHECK(pref_service_ == NULL);
   pref_service_ = pref_service;
 }