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

components/webauth/authenticator.mojom

+// 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.
+
+[JavaPackage="org.chromium.webauth.mojom"]
+module webauth.mojom;
+
+struct ScopedCredentialInfo {
+  array<uint8> client_data;
+  array<uint8> attestation;
+};
+
+struct RelyingPartyAccount {
+  string rp_display_name;
+  string display_name;
+  string id;
+  string name;
+  string image_url;
+};
+
+struct ScopedCredentialParameters {
+  ScopedCredentialType type;
+  // TODO(kpaulhamus): add AlgorithmIdentifier algorithm;
+};
+
+struct ScopedCredentialOptions {
+  int32 timeout_seconds;
+  string rp_id;
+  array<ScopedCredentialDescriptor> exclude_list;
+  // TODO(kpaulhamus): add Extensions
+};
+
+enum ScopedCredentialType {
+  SCOPEDCRED,
+};
+
+struct ScopedCredentialDescriptor {
+  ScopedCredentialType type;
+  array<uint8> id;
+  array<Transport> transports;
+};
+
+enum Transport {
+  USB,
+  NFC,
+  BLE,
+};
+
+interface Authenticator {
+  makeCredential(RelyingPartyAccount account_information,
+                 array<ScopedCredentialParameters> crypto_parameters,
+                 array<uint8> attestation_challenge,
+                 ScopedCredentialOptions? options)
+      => (array<ScopedCredentialInfo> scoped_credentials);
+};