Files app: Remove callback from launcher.launchFileManager()

Given that this function is async, we can remove callback and the caller
sites can use then() or "await" to chain additional work. This
simplifies the logic inside launchFileManager() method.

Bug: 1067478
Change-Id: I203370d5ff9dbb351df8bcd68696bae39630e5fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2147438Reviewed-by: Alex Danilo <adanilo@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759533}

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

@@ -334,7 +334,7 @@ class FileBrowserBackgroundImpl extends BackgroundBase {
         appState.selectionURL = urls[0];
         launchType = LaunchType.FOCUS_SAME_OR_CREATE;
       }
-      launcher.launchFileManager(appState, undefined, launchType, () => {
+      launcher.launchFileManager(appState, undefined, launchType).then(() => {
         metrics.recordInterval('Load.BackgroundLaunch');
       });
     });
@@ -368,7 +368,7 @@ class FileBrowserBackgroundImpl extends BackgroundBase {
             const id = Number(match[1]);
             try {
               const appState = /** @type {Object} */ (JSON.parse(items[key]));
-              launcher.launchFileManager(appState, id, undefined, () => {
+              launcher.launchFileManager(appState, id, undefined).then(() => {
                 metrics.recordInterval('Load.BackgroundRestart');
               });
             } catch (e) {

ui/file_manager/file_manager/background/js/launcher.js

@@ -69,10 +69,10 @@ launcher.setInitializationPromise = (promise) => {
  * @param {Object=} opt_appState App state.
  * @param {number=} opt_id Window id.
  * @param {LaunchType=} opt_type Launch type. Default: ALWAYS_CREATE.
- * @param {function(?string)=} opt_callback Completion callback with the App ID.
+ * @return {!Promise<chrome.app.window.AppWindow|string>} Resolved with the App
+ *     ID.
  */
-launcher.launchFileManager =
-    async (opt_appState, opt_id, opt_type, opt_callback) => {
+launcher.launchFileManager = async (opt_appState, opt_id, opt_type) => {
   const type = opt_type || LaunchType.ALWAYS_CREATE;
   opt_appState =
       /**
@@ -113,9 +113,6 @@ launcher.launchFileManager =
         continue;
       }
       window.appWindows[key].focus();
-      if (opt_callback) {
-        opt_callback(key);
-      }
       return Promise.resolve(key);
     }
   }
@@ -132,9 +129,6 @@ launcher.launchFileManager =
       // the Files app's failed on some error, wrap it with try catch.
       try {
         if (window.appWindows[key].contentWindow.isFocused()) {
-          if (opt_callback) {
-            opt_callback(key);
-          }
           return Promise.resolve(key);
         }
       } catch (e) {
@@ -149,9 +143,6 @@ launcher.launchFileManager =
 
       if (!window.appWindows[key].isMinimized()) {
         window.appWindows[key].focus();
-        if (opt_callback) {
-          opt_callback(key);
-        }
         return Promise.resolve(key);
       }
     }
@@ -162,9 +153,6 @@ launcher.launchFileManager =
       }
 
       window.appWindows[key].focus();
-      if (opt_callback) {
-        opt_callback(key);
-      }
       return Promise.resolve(key);
     }
   }
@@ -183,16 +171,11 @@ launcher.launchFileManager =
 
   const appWindow = new AppWindowWrapper(
       'main.html', appId, FILE_MANAGER_WINDOW_CREATE_OPTIONS);
-  appWindow.launch(opt_appState || {}, false).then(() => {
-    if (!appWindow.rawAppWindow) {
-      opt_callback && opt_callback(null);
-      return Promise.resolve(null);
-    }
+  await appWindow.launch(opt_appState || {}, false);
+  if (!appWindow.rawAppWindow) {
+    return null;
+  }
 
-    appWindow.rawAppWindow.focus();
-    if (opt_callback) {
-      opt_callback(appId);
-    }
-    return Promise.resolve(appId);
-  });
+  appWindow.rawAppWindow.focus();
+  return appId;
 };

ui/file_manager/file_manager/background/js/test_util.js

@@ -10,11 +10,13 @@
  *     App ID.
  */
 test.util.async.openMainWindow = (appState, callback) => {
-  launcher.launchFileManager(
-      appState,
-      undefined,  // opt_type
-      undefined,  // opt_id
-      callback);
+  launcher
+      .launchFileManager(
+          appState,
+          undefined,  // opt_type
+          undefined,  // opt_id
+          )
+      .then(callback);
 };
 
 /**