refactored use of for projects:tree:*

app/assets/javascripts/dispatcher.js

@@ -411,10 +411,9 @@ import { fetchCommitMergeRequests } from './commit_merge_requests';
           break;
         case 'projects:tree:show':
           import('./pages/projects/tree/show')
-            .then((module) => {
-              shortcut_handler = module.default();
-            })
+            .then(callDefault)
             .catch(fail);
+          shortcut_handler = true;
           break;
         case 'projects:find_file:show':
           const findElement = document.querySelector('.js-file-finder');

app/assets/javascripts/pages/projects/tree/show/index.js

@@ -5,12 +5,11 @@ import NewCommitForm from '../../../../new_commit_form';
 import { ajaxGet } from '../../../../lib/utils/common_utils';
 
 export default () => {
+  new ShortcutsNavigation(); // eslint-disable-line no-new
   new TreeView(); // eslint-disable-line no-new
   new BlobViewer(); // eslint-disable-line no-new
   new NewCommitForm($('.js-create-dir-form')); // eslint-disable-line no-new
   $('#tree-slider').waitForImages(() =>
     ajaxGet(document.querySelector('.js-tree-content').dataset.logsPath));
-
-  return new ShortcutsNavigation(); // eslint-disable-line no-new
 };