Introduce a new framework for back-and-forth tracked/protected preferences migration.

chrome/browser/prefs/profile_pref_store_manager.cc

Index: chrome/browser/prefs/profile_pref_store_manager.cc
diff --git a/chrome/browser/prefs/profile_pref_store_manager.cc b/chrome/browser/prefs/profile_pref_store_manager.cc
index e93cb8358117ec4bcf5c551f200ec899f4ef1a90..a0192ebaefe6cbb1e4350e0985f6e26065a71115 100644
--- a/chrome/browser/prefs/profile_pref_store_manager.cc
+++ b/chrome/browser/prefs/profile_pref_store_manager.cc
@@ -14,6 +14,7 @@
 #include "chrome/browser/prefs/pref_hash_store_impl.h"
 #include "chrome/browser/prefs/tracked/pref_service_hash_store_contents.h"
 #include "chrome/browser/prefs/tracked/segregated_pref_store.h"
+#include "chrome/browser/prefs/tracked/tracked_preferences_migration.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_prefs/pref_registry_syncable.h"
@@ -283,6 +284,7 @@ PersistentPrefStore* ProfilePrefStoreManager::CreateProfilePrefStore(
   std::vector<PrefHashFilter::TrackedPreferenceMetadata>
       protected_configuration;
   std::set<std::string> protected_pref_names;
+  std::set<std::string> unprotected_pref_names;
   for (std::vector<PrefHashFilter::TrackedPreferenceMetadata>::const_iterator
            it = tracking_configuration_.begin();
        it != tracking_configuration_.end();
@@ -292,6 +294,7 @@ PersistentPrefStore* ProfilePrefStoreManager::CreateProfilePrefStore(
       protected_pref_names.insert(it->name);
     } else {
       unprotected_configuration.push_back(*it);
+      unprotected_pref_names.insert(it->name);
     }
   }
 
@@ -304,29 +307,22 @@ PersistentPrefStore* ProfilePrefStoreManager::CreateProfilePrefStore(
                          protected_configuration,
                          reporting_ids_count_));
 
-  scoped_refptr<PersistentPrefStore> unprotected_pref_store(
+  scoped_refptr<JsonPrefStore> unprotected_pref_store(
       new JsonPrefStore(GetPrefFilePathFromProfilePath(profile_path_),
                         io_task_runner,
                         unprotected_pref_hash_filter.Pass()));
-  scoped_refptr<PersistentPrefStore> protected_pref_store(new JsonPrefStore(
+  scoped_refptr<JsonPrefStore> protected_pref_store(new JsonPrefStore(
       profile_path_.Append(chrome::kProtectedPreferencesFilename),
       io_task_runner,
       protected_pref_hash_filter.Pass()));
 
-  // The on_initialized callback is used to migrate newly protected values from
-  // the main Preferences store to the Protected Preferences store. It is also
-  // responsible for the initial migration to a two-store model.
-  return new SegregatedPrefStore(
-      unprotected_pref_store,
-      protected_pref_store,
-      protected_pref_names,
-      base::Bind(&PrefHashFilter::MigrateValues,
-                 base::Owned(new PrefHashFilter(
-                     CopyPrefHashStore(),
-                     protected_configuration,
-                     reporting_ids_count_)),
-                 unprotected_pref_store,
-                 protected_pref_store));
+  SetupTrackedPreferencesMigration(unprotected_pref_names,
+                                   protected_pref_names,
+                                   unprotected_pref_store,
+                                   protected_pref_store);
+
+  return new SegregatedPrefStore(unprotected_pref_store, protected_pref_store,
+                                 protected_pref_names);
 }
 
 void ProfilePrefStoreManager::UpdateProfileHashStoreIfRequired(
@@ -410,15 +406,3 @@ scoped_ptr<PrefHashStoreImpl> ProfilePrefStoreManager::GetPrefHashStoreImpl() {
       scoped_ptr<HashStoreContents>(new PrefServiceHashStoreContents(
           profile_path_.AsUTF8Unsafe(), local_state_))));
 }
-
-scoped_ptr<PrefHashStore> ProfilePrefStoreManager::CopyPrefHashStore() {
-  DCHECK(kPlatformSupportsPreferenceTracking);
-
-  PrefServiceHashStoreContents real_contents(profile_path_.AsUTF8Unsafe(),
-                                             local_state_);
-  return scoped_ptr<PrefHashStore>(new PrefHashStoreImpl(
-      seed_,
-      device_id_,
-      scoped_ptr<HashStoreContents>(
-          new DictionaryHashStoreContents(real_contents))));
-}