Integrate registry_hash_store_contents with the rest of tracked prefs.

components/prefs/json_pref_store_unittest.cc

 // 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.
 
 #include "components/prefs/json_pref_store.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
@@ skipping 58 matching lines @@
 class InterceptingPrefFilter : public PrefFilter {
  public:
   InterceptingPrefFilter();
   ~InterceptingPrefFilter() override;
 
   // PrefFilter implementation:
   void FilterOnLoad(
       const PostFilterOnLoadCallback& post_filter_on_load_callback,
       std::unique_ptr<base::DictionaryValue> pref_store_contents) override;
   void FilterUpdate(const std::string& path) override {}
-  void FilterSerializeData(
-      base::DictionaryValue* pref_store_contents) override {}
+  base::Callback<void(bool)> FilterSerializeData(
+      base::DictionaryValue* pref_store_contents) override {
+    return base::Callback<void(bool)>();
+  }
 
   bool has_intercepted_prefs() const { return intercepted_prefs_ != NULL; }
 
   // Finalize an intercepted read, handing |intercepted_prefs_| back to its
   // JsonPrefStore.
   void ReleasePrefs();
 
  private:
   PostFilterOnLoadCallback post_filter_on_load_callback_;
   std::unique_ptr<base::DictionaryValue> intercepted_prefs_;
@@ skipping 1078 matching lines @@
     write_callback_observer_.ObserveNextWriteCallback(
         soon_out_of_scope_pref_store.get());
     file_writer->WriteNow(MakeUnique<std::string>("foo"));
   }
   RunLoop().RunUntilIdle();
   EXPECT_FALSE(successful_write_reply_observer_.GetAndResetObservationState());
   EXPECT_EQ(CALLED_WITH_SUCCESS,
             write_callback_observer_.GetAndResetObservationState());
 }
 
-}  // namespace base
+}  // namespace base