This CL fixes that physical keyboard layout is not changed when user
changes it in settings. This happened because we compare
InputDeviceIdentifier instances by using Object#equals to choose
specified input device. However, one of them has been serialized and
deserialized, so it never be true.
Bug: 27747115
Change-Id: Ied84c510ccb8e2de919ba8bb326e0355a065e604