fix(auth): Update to rxjs pipeable operators (angular#1621)

Author: jymdman

src/auth/auth.spec.ts

@@ -1,15 +1,11 @@
 import { User } from '@firebase/auth-types';
 import { ReflectiveInjector, Provider } from '@angular/core';
-import { Observable } from 'rxjs/Observable'
-import { Subject } from 'rxjs/Subject'
-import { Observer } from 'rxjs/Observer';
+import { Observable, Subject } from 'rxjs'
 import { TestBed, inject } from '@angular/core/testing';
-import { _do } from 'rxjs/operator/do';
-import { take } from 'rxjs/operator/take';
-import { skip } from 'rxjs/operator/skip';
 import { FirebaseApp, FirebaseAppConfig, AngularFireModule, FirebaseAppName } from 'angularfire2';
 import { AngularFireAuth, AngularFireAuthModule } from 'angularfire2/auth';
 import { COMMON_CONFIG } from './test-config';
+import { take, skip } from 'rxjs/operators';
 
 function authTake(auth: Observable<any>, count: number): Observable<any> {
   return take.call(auth, 1);

src/auth/auth.ts

@@ -1,13 +1,13 @@
 import { FirebaseAuth, User } from '@firebase/auth-types';
 import { FirebaseOptions } from '@firebase/app-types';
 import { Injectable, Inject, Optional, NgZone, PLATFORM_ID } from '@angular/core';
-import { Observable } from 'rxjs/Observable';
+import { Observable } from 'rxjs';
+import { switchMap } from 'rxjs/operators';
+import { of } from 'rxjs/observable/of';
+import { from } from 'rxjs/observable/from';
 
 import { FirebaseAppConfig, FirebaseAppName, _firebaseAppFactory, FirebaseZoneScheduler } from 'angularfire2';
 
-import 'rxjs/add/operator/switchMap';
-import 'rxjs/add/observable/of';
-import 'rxjs/add/observable/fromPromise';
 
 @Injectable()
 export class AngularFireAuth {
@@ -55,10 +55,9 @@ export class AngularFireAuth {
           return { unsubscribe };
         })
       )
-    ).switchMap((user:User|null) => {
-      return user ? Observable.fromPromise(user.getIdToken()) : Observable.of(null)
-    });
-
+    ).pipe(switchMap((user:User) => {
+      return user ? from(user.getIdToken()) : of(null)
+    }));    
   }
 
 }