Removed a context menu from Files.app's left nav, since it became redundant.

chrome/browser/resources/file_manager/js/file_manager_commands.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var CommandUtil = {};
 
 /**
  * Extracts root on which command event was dispatched.
  *
  * @param {Event} event Command event for which to retrieve root to operate on.
@@ skipping 386 matching lines @@
     fileManager.copyManager_.zipSelection(dirEntry, fileManager.isOnDrive(),
                                           selectionEntries);
   },
   canExecute: function(event, fileManager) {
     var selection = fileManager.getSelection();
     event.canExecute = !fileManager.isOnReadonlyDirectory() &&
         !fileManager.isOnDrive() &&
         selection && selection.totalCount > 0;
   }
 };
-
-/**
- * Opens Files App help.
- */
-Commands.filesAppHelpCommand = {
-  execute: function() {
-    window.open(FileManager.FILES_APP_HELP, 'help');
-  },
-  canExecute: function(event, fileManager) {
-    event.canExecute = true;
-  }
-};