ChromeOS: Add RenameCryptohome and migration code.

chromeos/dbus/fake_cryptohome_client.cc

Index: chromeos/dbus/fake_cryptohome_client.cc
diff --git a/chromeos/dbus/fake_cryptohome_client.cc b/chromeos/dbus/fake_cryptohome_client.cc
index 2ae919761587671c8dae6a6dcb6f5e6498291073..e85161c0cec402633d2d56e44e08c2c2e79aeac6 100644
--- a/chromeos/dbus/fake_cryptohome_client.cc
+++ b/chromeos/dbus/fake_cryptohome_client.cc
@@ -93,6 +93,14 @@ void FakeCryptohomeClient::AsyncRemove(
   ReturnAsyncMethodResult(callback, false);
 }
 
+void FakeCryptohomeClient::RenameCryptohome(
+    const cryptohome::Identification& cryptohome_id_from,
+    const cryptohome::Identification& cryptohome_id_to,
+    const ProtobufMethodCallback& callback) {
+  cryptohome::BaseReply reply;
+  ReturnProtobufMethodCallback(reply, callback);
+}
+
 void FakeCryptohomeClient::GetSystemSalt(
     const GetSystemSaltCallback& callback) {
   base::MessageLoop::current()->PostTask(