Pull GetMutableValue from Perisistent to WritablePrefStore.

base/prefs/value_map_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_VALUE_MAP_PREF_STORE_H_
 #define BASE_PREFS_VALUE_MAP_PREF_STORE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 12 matching lines @@
   // PrefStore overrides:
   virtual bool GetValue(const std::string& key,
                         const base::Value** value) const OVERRIDE;
   virtual void AddObserver(PrefStore::Observer* observer) OVERRIDE;
   virtual void RemoveObserver(PrefStore::Observer* observer) OVERRIDE;
   virtual bool HasObservers() const OVERRIDE;
 
   // WriteablePrefStore overrides:
   virtual void SetValue(const std::string& key, base::Value* value) OVERRIDE;
   virtual void RemoveValue(const std::string& key) OVERRIDE;
+  virtual bool GetMutableValue(const std::string& key,
+                               base::Value** value) OVERRIDE;
+  virtual void ReportValueChanged(const std::string& key) OVERRIDE;
 
  protected:
   virtual ~ValueMapPrefStore();
 
   // Notify observers about the initialization completed event.
   void NotifyInitializationCompleted();
 
  private:
   PrefValueMap prefs_;
 
   ObserverList<PrefStore::Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ValueMapPrefStore);
 };
 
 #endif  // BASE_PREFS_VALUE_MAP_PREF_STORE_H_