[Files app] Removed callback from volumeManagerFactory.getInstance()

Change-Id: Id668076353fc0a3a956fe7c742a3971c1d4f6f78
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619451
Commit-Queue: François Degros <fdegros@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Auto-Submit: François Degros <fdegros@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661278}

ui/file_manager/base/js/filtered_volume_manager.js

@@ -105,11 +105,14 @@ class FilteredVolumeManager extends cr.EventTarget {
       });
     }
 
-    queue.run(callNextStep => {
-      this.backgroundPage_.volumeManagerFactory.getInstance(volumeManager => {
+    queue.run(async (callNextStep) => {
+      try {
+        const volumeManager =
+            await this.backgroundPage_.volumeManagerFactory.getInstance();
         this.onReady_(volumeManager);
+      } finally {
         callNextStep();
-      });
+      }
     });
   }
 

ui/file_manager/externs/background/volume_manager_factory.js

@@ -5,10 +5,9 @@
 var volumeManagerFactory = {};
 
 /**
- * @param {function(VolumeManager)=} opt_callback
- * @return {Promise}
+ * @return {!Promise<!VolumeManager>}
  */
-volumeManagerFactory.getInstance = function(opt_callback) {};
+volumeManagerFactory.getInstance = function() {};
 
 /**
  * @return {VolumeManager}

ui/file_manager/file_manager/background/js/volume_manager_factory.js

@@ -19,21 +19,15 @@ var volumeManagerFactory = (() => {
    * Returns the VolumeManager instance asynchronously. If it has not been
    * created or is under initialization, it will waits for the finish of the
    * initialization.
-   * @param {function(VolumeManager)=} opt_callback Called with the
-   *     VolumeManager instance. TODO(hirono): Remove the callback and use
-   *     Promise instead.
    * @return {!Promise<!VolumeManager>} Promise to be fulfilled with the volume
    *     manager.
    */
-  function getInstance(opt_callback) {
+  function getInstance() {
     if (!instancePromise) {
       instance = new VolumeManagerImpl();
       instancePromise =
           new Promise(fulfill => instance.initialize(() => fulfill(instance)));
     }
-    if (opt_callback) {
-      instancePromise.then(opt_callback);
-    }
     return instancePromise;
   }