Patch #1 of multiple. Add webauth .mojom and initial usage of makeCredential.

third_party/WebKit/Source/modules/webauth/WebAuthentication.idl

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // https://w3c.github.io/webauthn/#webauthentication
 
 [
     RuntimeEnabled=WebAuth,
     SecureContext
 ] interface WebAuthentication {
-    [CallWith=ScriptState] Promise<sequence<ScopedCredentialInfo>> makeCredential(RelyingPartyAccount accountInformation, sequence<ScopedCredentialParameters> cryptoParameters, BufferSource attestationChallenge, optional ScopedCredentialOptions options);
-    [CallWith=ScriptState] Promise<sequence<WebAuthnAssertion>> getAssertion(BufferSource assertionChallenge, optional AuthenticationAssertionOptions options);
+    [CallWith=ScriptState] Promise<sequence<ScopedCredentialInfo>> MakeCredential(RelyingPartyAccount accountInformation, sequence<ScopedCredentialParameters> cryptoParameters, BufferSource attestationChallenge, optional ScopedCredentialOptions options);

[dcheng, 2017/05/04 07:22:35]

WebIDL methods should be named makeCredential() and getAssertion() to match
web-style naming. It's a bit confusing, but the rule is:
- Things that are directly implementing a function called by IDL bindings should
be namedLikedThis(): this way, the C++ tests resemble the way JS looks more
closely in terms of style and naming.
- Things that are just supporting functionality defined in WebIDL or helper
functions, etc. should be NamedLikeThis().

[kpaulhamus, 2017/05/05 01:32:36]

Ah, okay, I'm finally getting it. Yeah, the rename happened in the middle of
this and I got mixed up.

+    [CallWith=ScriptState] Promise<sequence<WebAuthnAssertion>> GetAssertion(BufferSource assertionChallenge, optional AuthenticationAssertionOptions options);
 };