Implement the mechanics of fxa login on android, but don't show ui fo… (#1000)

* Implement the mechanics of fxa login on android, but don't show ui for it yet. Also, scopedKeys are not yet implemented.

* Hopefully fix the package-lock conflict?

* WIP on android scoped keys

* Finish implementing login.

* created android/user.js to handle android logins

android/user.js

@@ -0,0 +1,26 @@
+/* global Android */
+import User from '../app/user';
+import { deriveFileListKey } from '../app/fxa';
+
+export default class AndroidUser extends User {
+  constructor(storage) {
+    super(storage);
+  }
+
+  async login() {
+    Android.beginOAuthFlow();
+  }
+
+  async finishLogin(accountInfo) {
+    const jwks = JSON.parse(accountInfo.keys);
+    const ikm = jwks['https://identity.mozilla.com/apps/send'].k;
+    const profile = {
+      displayName: accountInfo.displayName,
+      email: accountInfo.email,
+      avatar: accountInfo.avatar,
+      access_token: accountInfo.accessToken
+    };
+    profile.fileListKey = await deriveFileListKey(ikm);
+    this.info = profile;
+  }
+}