Holes are the new notches Huawei is considering cutting a slit for the earpiece as revealed by a design patent filed with the USPTO. This is interesting, because the expectation was that holes will be used for selfie cameras (like in Samsungs Infinity-O design and teased with the Galaxy A8s).
In fact, the patent doesnt mention the selfie camera at all. A Huawei design that leaked in July showed a camera in the hole and the earpiece on the bezel above it. That design also envisioned an in-display fingerprint reader while this patent seems to place it under the camera on the back. Huawei is clearly exploring various designs
Anyway, why so much effort for an earpiece? Some phones (like the original Mi Mix) tried to use a piezoelectric speaker to put the earpiece behind the screen. However, the sound quality proved to be pretty poor. A proper grille will offer superior audio.