Delete the PreferenceMACs on profile deletion.

services/preferences/tracked/segregated_pref_store.h

 // Copyright 2014 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 SERVICES_PREFERENCES_TRACKED_SEGREGATED_PREF_STORE_H_
 #define SERVICES_PREFERENCES_TRACKED_SEGREGATED_PREF_STORE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 56 matching lines @@
   void ReportValueChanged(const std::string& key, uint32_t flags) override;
   void SetValueSilently(const std::string& key,
                         std::unique_ptr<base::Value> value,
                         uint32_t flags) override;
   bool ReadOnly() const override;
   PrefReadError GetReadError() const override;
   PrefReadError ReadPrefs() override;
   void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
   void CommitPendingWrite(base::OnceClosure done_callback) override;
   void SchedulePendingLossyWrites() override;
-
   void ClearMutableValues() override;
+  void OnStoreDeletionFromDisk() override;
 
  private:
   // Aggregates events from the underlying stores and synthesizes external
   // events via |on_initialization|, |read_error_delegate_|, and |observers_|.
   class AggregatingObserver : public PrefStore::Observer {
    public:
     explicit AggregatingObserver(SegregatedPrefStore* outer);
 
     // PrefStore::Observer implementation
     void OnPrefValueChanged(const std::string& key) override;
@@ skipping 24 matching lines @@
   std::set<std::string> selected_preference_names_;
 
   std::unique_ptr<PersistentPrefStore::ReadErrorDelegate> read_error_delegate_;
   base::ObserverList<PrefStore::Observer, true> observers_;
   AggregatingObserver aggregating_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(SegregatedPrefStore);
 };
 
 #endif  // SERVICES_PREFERENCES_TRACKED_SEGREGATED_PREF_STORE_H_