Update from https://crrev.com/333737

base/prefs/json_pref_store.h

 // 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.
 
 #ifndef BASE_PREFS_JSON_PREF_STORE_H_
 #define BASE_PREFS_JSON_PREF_STORE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 80 matching lines @@
                         uint32 flags) override;
   void RemoveValue(const std::string& key, uint32 flags) override;
   bool ReadOnly() const override;
   PrefReadError GetReadError() const override;
   // Note this method may be asynchronous if this instance has a |pref_filter_|
   // in which case it will return PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE.
   // See details in pref_filter.h.
   PrefReadError ReadPrefs() override;
   void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
   void CommitPendingWrite() override;
+  void SchedulePendingLossyWrites() override;
   void ReportValueChanged(const std::string& key, uint32 flags) override;
 
   // Just like RemoveValue(), but doesn't notify observers. Used when doing some
   // cleanup that shouldn't otherwise alert observers.
   void RemoveValueSilently(const std::string& key, uint32 flags);
 
   // Registers |on_next_successful_write| to be called once, on the next
   // successful write event of |writer_|.
   void RegisterOnNextSuccessfulWriteCallback(
       const base::Closure& on_next_successful_write);
@@ skipping 90 matching lines @@
   const scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
 
   scoped_ptr<base::DictionaryValue> prefs_;
 
   bool read_only_;
 
   // Helper for safely writing pref data.
   base::ImportantFileWriter writer_;
 
   scoped_ptr<PrefFilter> pref_filter_;
-  ObserverList<PrefStore::Observer, true> observers_;
+  base::ObserverList<PrefStore::Observer, true> observers_;
 
   scoped_ptr<ReadErrorDelegate> error_delegate_;
 
   bool initialized_;
   bool filtering_in_progress_;
   bool pending_lossy_write_;
   PrefReadError read_error_;
 
   std::set<std::string> keys_need_empty_value_;
 
   WriteCountHistogram write_count_histogram_;
 
   DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
 };
 
 #endif  // BASE_PREFS_JSON_PREF_STORE_H_