Move preference MACs to the protected preference stores.

chrome/browser/prefs/pref_hash_filter.h

Index: chrome/browser/prefs/pref_hash_filter.h
diff --git a/chrome/browser/prefs/pref_hash_filter.h b/chrome/browser/prefs/pref_hash_filter.h
index f195f1cc136a064abd132ffc33681461954430e3..c588286fae1959017c1013df8f767be4b1596524 100644
--- a/chrome/browser/prefs/pref_hash_filter.h
+++ b/chrome/browser/prefs/pref_hash_filter.h
@@ -82,12 +82,12 @@ class PrefHashFilter : public InterceptablePrefFilter {
 
   // Initializes the PrefHashStore with hashes of the tracked preferences in
   // |pref_store|.
-  void Initialize(const PrefStore& pref_store);
+  void Initialize(base::DictionaryValue* pref_store_contents);
 
   // PrefFilter remaining implementation.
   virtual void FilterUpdate(const std::string& path) OVERRIDE;
   virtual void FilterSerializeData(
-      const base::DictionaryValue* pref_store_contents) OVERRIDE;
+      base::DictionaryValue* pref_store_contents) OVERRIDE;
 
  private:
   // InterceptablePrefFilter implementation.