feat(storage): address Ben's comments

Author: davideast

src/storage/observable/fromTask.ts

@@ -1,14 +1,12 @@
 import { storage } from 'firebase/app';
-import 'firebase/storage';
 import { Observable } from 'rxjs/Observable';
 
 export function fromTask(task: storage.UploadTask) {
   return new Observable<storage.UploadTaskSnapshot | undefined>(subscriber => {
-    task.on('state_changed', 
-      (snap: storage.UploadTaskSnapshot) => subscriber.next(snap),
-      e => subscriber.error(e),
-      () => subscriber.complete()
-    );
-    return { unsubscribe: task.cancel };
+    const progress = (snap: storage.UploadTaskSnapshot) => subscriber.next(snap);
+    const error = e => subscriber.error(e);
+    const complete = () => subscriber.complete();
+    task.on('state_changed', progress, error, complete);
+    return () => task.cancel();
   });
 }

src/storage/storage.spec.ts

@@ -58,7 +58,7 @@ describe('AngularFireStorage', () => {
       const task = ref.put(blob);
       const url$ = task.downloadURL();
       url$.subscribe(
-        url => { console.log(url); expect(url).toBeDefined(); },
+        url => { expect(url).toBeDefined(); },
         e => { done.fail(); },
         () => { ref.delete().subscribe(done, done.fail); }
       );

src/storage/task.ts

@@ -1,7 +1,7 @@
 import { storage } from 'firebase/app';
 import { fromTask } from './observable/fromTask';
 import { Observable } from 'rxjs/Observable';
-import { map, filter, shareReplay } from 'rxjs/operators';
+import { map, filter } from 'rxjs/operators';
 
 export interface AngularFireUploadTask {
   snapshotChanges(): Observable<storage.UploadTaskSnapshot | undefined>;
@@ -15,7 +15,7 @@ export interface AngularFireUploadTask {
 }
 
 export function createUploadTask(task: storage.UploadTask): AngularFireUploadTask {
-  const inner$ = fromTask(task).pipe(shareReplay());
+  const inner$ = fromTask(task);
   return { 
     pause() { return task.pause(); },    
     cancel() { return task.cancel(); },