Update from https://crrev.com/306655

base/prefs/pref_notifier_impl_unittest.cc

 // Copyright (c) 2011 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/bind.h"
 #include "base/callback.h"
 #include "base/prefs/mock_pref_change_callback.h"
 #include "base/prefs/pref_notifier_impl.h"
 #include "base/prefs/pref_observer.h"
 #include "base/prefs/pref_registry_simple.h"
@@ skipping 33 matching lines @@
 
 // Mock PrefNotifier that allows tracking of observers and notifications.
 class MockPrefNotifier : public PrefNotifierImpl {
  public:
   explicit MockPrefNotifier(PrefService* pref_service)
       : PrefNotifierImpl(pref_service) {}
   virtual ~MockPrefNotifier() {}
 
   MOCK_METHOD1(FireObservers, void(const std::string& path));
 
-  size_t CountObserver(const char* path, PrefObserver* obs) {
+  size_t CountObserver(const std::string& path, PrefObserver* obs) {
     PrefObserverMap::const_iterator observer_iterator =
         pref_observers()->find(path);
     if (observer_iterator == pref_observers()->end())
       return false;
 
     PrefObserverList* observer_list = observer_iterator->second;
     PrefObserverList::Iterator it(*observer_list);
     PrefObserver* existing_obs;
     size_t count = 0;
     while ((existing_obs = it.GetNext()) != NULL) {
@@ skipping 146 matching lines @@
   EXPECT_CALL(obs2_, OnPreferenceChanged(&pref_service_, kChangedPref));
   notifier.OnPreferenceChanged(kChangedPref);
   Mock::VerifyAndClearExpectations(&obs1_);
   Mock::VerifyAndClearExpectations(&obs2_);
 
   notifier.RemovePrefObserver(kChangedPref, &obs2_);
   notifier.RemovePrefObserver(kUnchangedPref, &obs2_);
 }
 
 }  // namespace