Add support for ImplementedAs for Dictionary members. Currently, I didn't see a way to implement: https://www.w3.org/TR/WebCryptoAPI/#dh-EcdhKeyDeriveParams as public is a reserved word in C++.
Currently, I have to reconstruct a new JSObject on the fly with a better name publicKey for the public member and then convert the newly constructed JSObject into native one. However, when there is a TypeError, we generate this awkward messages: crypto.subtle.deriveBits({ name:"ECDH", publicKey:wrongKey }, wrongKey, 128) rejected promise with TypeError: Member EcdhKeyDeriveParams.publicKey is required and must be an instance of CryptoKey.
*** This bug has been marked as a duplicate of bug 169731 ***