Fix circular dependency issue

Author: sam-gc

packages-exp/auth-exp/src/core/credentials/auth_credential.ts

@@ -18,7 +18,6 @@
 import { PhoneOrOauthTokenResponse } from '../../api/authentication/mfa';
 import { AuthCore } from '../../model/auth';
 import { IdTokenResponse } from '../../model/id_token';
-import { EmailAuthCredential, OAuthCredential, PhoneAuthCredential } from './';
 import { debugFail } from '../util/assert';
 
 export class AuthCredential {
@@ -27,21 +26,6 @@ export class AuthCredential {
     readonly signInMethod: string
   ) {}
 
-  static fromJSON(json: object | string): AuthCredential | null {
-    for (const fn of [
-      /* SAMLAuthCredential.fromJSON, */
-      OAuthCredential.fromJSON,
-      EmailAuthCredential.fromJSON,
-      PhoneAuthCredential.fromJSON
-    ]) {
-      const credential = fn(json);
-      if (credential) {
-        return credential;
-      }
-    }
-    return null;
-  }
-
   toJSON(): object {
     return debugFail('not implemented');
   }

packages-exp/auth-exp/src/core/credentials/email.ts

@@ -20,14 +20,13 @@ import * as externs from '@firebase/auth-types-exp';
 import { updateEmailPassword } from '../../api/account_management/email_and_password';
 import { signInWithPassword } from '../../api/authentication/email_and_password';
 import {
-  signInWithEmailLink,
-  signInWithEmailLinkForLinking
+    signInWithEmailLink, signInWithEmailLinkForLinking
 } from '../../api/authentication/email_link';
 import { AuthCore } from '../../model/auth';
 import { IdTokenResponse } from '../../model/id_token';
 import { AuthErrorCode } from '../errors';
 import { fail } from '../util/assert';
-import { AuthCredential } from './';
+import { AuthCredential } from './auth_credential';
 
 export class EmailAuthCredential
   extends AuthCredential

packages-exp/auth-exp/src/core/credentials/oauth.ts

@@ -18,15 +18,12 @@
 import * as externs from '@firebase/auth-types-exp';
 import { querystring } from '@firebase/util';
 
-import {
-  signInWithIdp,
-  SignInWithIdpRequest
-} from '../../api/authentication/idp';
+import { signInWithIdp, SignInWithIdpRequest } from '../../api/authentication/idp';
 import { AuthCore } from '../../model/auth';
+import { IdTokenResponse } from '../../model/id_token';
 import { AuthErrorCode } from '../errors';
 import { fail } from '../util/assert';
-import { AuthCredential } from './';
-import { IdTokenResponse } from '../../model/id_token';
+import { AuthCredential } from './auth_credential';
 
 const IDP_REQUEST_URI = 'http://localhost';
 

packages-exp/auth-exp/src/core/credentials/phone.ts

@@ -19,14 +19,12 @@ import * as externs from '@firebase/auth-types-exp';
 
 import { PhoneOrOauthTokenResponse } from '../../api/authentication/mfa';
 import {
-  linkWithPhoneNumber,
-  signInWithPhoneNumber,
-  SignInWithPhoneNumberRequest,
-  verifyPhoneNumberForExisting
+    linkWithPhoneNumber, signInWithPhoneNumber, SignInWithPhoneNumberRequest,
+    verifyPhoneNumberForExisting
 } from '../../api/authentication/sms';
 import { AuthCore } from '../../model/auth';
 import { IdTokenResponse } from '../../model/id_token';
-import { AuthCredential } from './';
+import { AuthCredential } from './auth_credential';
 
 export interface PhoneAuthCredentialParameters {
   verificationId?: string;