[Sync] Implement keystore migration support.

sync/engine/apply_control_data_updates.cc

Index: sync/engine/apply_control_data_updates.cc
diff --git a/sync/engine/apply_control_data_updates.cc b/sync/engine/apply_control_data_updates.cc
index 2aa7dd4acfad3afd0ae60c04468269a51c0a7d29..7a52e8c36c58f5f6ec522e06aad5396a8b794b84 100644
--- a/sync/engine/apply_control_data_updates.cc
+++ b/sync/engine/apply_control_data_updates.cc
@@ -117,9 +117,9 @@ bool ApplyNigoriUpdates(syncable::WriteTransaction* trans,
     // that passphrase as an explicit one via settings. The goal here is to
     // ensure both sets of encryption keys are preserved.
     if (cryptographer->is_ready()) {
-      cryptographer->GetKeys(server_nigori->mutable_encrypted());
-      server_nigori->set_using_explicit_passphrase(
-          nigori_node.Get(SPECIFICS).nigori().using_explicit_passphrase());
+      cryptographer->GetKeys(server_nigori->mutable_encryption_keybag());
+      server_nigori->set_keybag_is_frozen(
+          nigori_node.Get(SPECIFICS).nigori().keybag_is_frozen());
     }
     nigori_node.Put(SPECIFICS, specifics);
     DVLOG(1) << "Resolving simple conflict, merging nigori nodes: "