Update from https://crrev.com/333737

base/prefs/overlay_user_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_OVERLAY_USER_PREF_STORE_H_
 #define BASE_PREFS_OVERLAY_USER_PREF_STORE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 33 matching lines @@
                 uint32 flags) override;
   void SetValueSilently(const std::string& key,
                         base::Value* value,
                         uint32 flags) override;
   void RemoveValue(const std::string& key, uint32 flags) override;
   bool ReadOnly() const override;
   PrefReadError GetReadError() const override;
   PrefReadError ReadPrefs() override;
   void ReadPrefsAsync(ReadErrorDelegate* delegate) override;
   void CommitPendingWrite() override;
+  void SchedulePendingLossyWrites() override;
   void ReportValueChanged(const std::string& key, uint32 flags) override;
 
   // Methods of PrefStore::Observer.
   void OnPrefValueChanged(const std::string& key) override;
   void OnInitializationCompleted(bool succeeded) override;
 
   void RegisterOverlayPref(const std::string& key);
   void RegisterOverlayPref(const std::string& overlay_key,
                            const std::string& underlay_key);
 
  protected:
   ~OverlayUserPrefStore() override;
 
  private:
   typedef std::map<std::string, std::string> NamesMap;
 
   const std::string& GetOverlayKey(const std::string& underlay_key) const;
   const std::string& GetUnderlayKey(const std::string& overlay_key) const;
 
   // Returns true if |key| corresponds to a preference that shall be stored in
   // an in-memory PrefStore that is not persisted to disk.
   bool ShallBeStoredInOverlay(const std::string& key) const;
 
-  ObserverList<PrefStore::Observer, true> observers_;
+  base::ObserverList<PrefStore::Observer, true> observers_;
   PrefValueMap overlay_;
   scoped_refptr<PersistentPrefStore> underlay_;
   NamesMap overlay_to_underlay_names_map_;
   NamesMap underlay_to_overlay_names_map_;
 
   DISALLOW_COPY_AND_ASSIGN(OverlayUserPrefStore);
 };
 
 #endif  // BASE_PREFS_OVERLAY_USER_PREF_STORE_H_