Adoption of Curve25519 ECDH will probably happen substantially before adoption of Ed25519 EdDSA, since it’s easier.
Currently this is the applicable draft, which is due to be adopted by the CURDLE WG. https://tools.ietf.org/html/draft-josefsson-pkix-newcurves-01
Of course this doesn’t obstruct implementations prior to ratification. In fact, this appears to have happened already: https://www.chromestatus.com/feature/5682529109540864
Edit: Confirming that BoringSSL, Google’s OpenSSL fork, supports Curve25519 ECDH.