Move preference MACs to the protected preference stores.

chrome/browser/prefs/tracked/tracked_preferences_migration.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 CHROME_BROWSER_PREFS_TRACKED_TRACKED_PREFERENCES_MIGRATION_H_
 #define CHROME_BROWSER_PREFS_TRACKED_TRACKED_PREFERENCES_MIGRATION_H_
 
 #include <set>
 #include <string>
 
 #include "base/callback_forward.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/prefs/pref_hash_store.h"
 
+class HashStoreContents;
 class InterceptablePrefFilter;
+class PrefHashStore;
 
 // Sets up InterceptablePrefFilter::FilterOnLoadInterceptors on
 // |unprotected_pref_filter| and |protected_pref_filter| which prevents each
 // filter from running their on load operations until the interceptors decide to
 // hand the prefs back to them (after migration is complete). |
 // (un)protected_store_cleaner| and
 // |register_on_successful_(un)protected_store_write_callback| are used to do
 // post-migration cleanup tasks. Those should be bound to weak pointers to avoid
-// blocking shutdown. The migration framework is resilient to a failed cleanup
-// (it will simply try again in the next Chrome run).
+// blocking shutdown. |(un)protected_pref_hash_store| and
+// |legacy_pref_hash_store| are used to migrate MACs along with their protected
+// preferences and/or from the legacy location in Local State. Migrated MACs
+// will only be cleared from their old location in a subsequent run. The
+// migration framework is resilient to a failed cleanup (it will simply try
+// again in the next Chrome run).
 void SetupTrackedPreferencesMigration(
     const std::set<std::string>& unprotected_pref_names,
     const std::set<std::string>& protected_pref_names,
     const base::Callback<void(const std::string& key)>&
         unprotected_store_cleaner,
     const base::Callback<void(const std::string& key)>& protected_store_cleaner,
     const base::Callback<void(const base::Closure&)>&
         register_on_successful_unprotected_store_write_callback,
     const base::Callback<void(const base::Closure&)>&
         register_on_successful_protected_store_write_callback,
+    scoped_ptr<PrefHashStore> unprotected_pref_hash_store,
+    scoped_ptr<PrefHashStore> protected_pref_hash_store,
+    scoped_ptr<HashStoreContents> legacy_pref_hash_store,
     InterceptablePrefFilter* unprotected_pref_filter,
     InterceptablePrefFilter* protected_pref_filter);
 
 #endif  // CHROME_BROWSER_PREFS_TRACKED_TRACKED_PREFERENCES_MIGRATION_H_