ChromeOS cryptohome should be able to use gaia id as user identifier.

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 236b1f95506dcd3818ae70bb5ac7217d9e84bd51..22bf3546121610c989f8530f94c2dd2e42c008e2 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::AccountIdentifier& id_from,
+    const cryptohome::AccountIdentifier& id_to,
+    const ProtobufMethodCallback& callback) {
+  cryptohome::BaseReply reply;
+  ReturnProtobufMethodCallback(reply, callback);
+}
+
 void FakeCryptohomeClient::GetSystemSalt(
     const GetSystemSaltCallback& callback) {
   base::MessageLoop::current()->PostTask(
@@ -489,7 +497,7 @@ void FakeCryptohomeClient::MountEx(
   cryptohome::BaseReply reply;
   cryptohome::MountReply* mount =
       reply.MutableExtension(cryptohome::MountReply::reply);
-  mount->set_sanitized_username(GetStubSanitizedUsername(id.email()));
+  mount->set_sanitized_username(GetStubSanitizedUsername(id.account_id()));
   ReturnProtobufMethodCallback(reply, callback);
 }