cros: Fix file open rescan directory callback on Linux

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

 // Copyright (c) 2011 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.
 
 // Setting the src of an img to an empty string can crash the browser, so we
 // use an empty 1x1 gif instead.
 const EMPTY_IMAGE_URI = 'data:image/gif;base64,'
         + 'R0lGODlhAQABAPABAP///wAAACH5BAEKAAAALAAAAAABAAEAAAICRAEAOw%3D%3D';
 
 var g_slideshow_data = null;
@@ skipping 3051 matching lines @@
       return;
     }
 
     // Otherwise, use the provided list of root subdirectories, since the
     // real local filesystem root directory (the one we use outside the
     // harness) can't be enumerated yet.
     var spliceArgs = [].slice.call(this.rootEntries_);
     spliceArgs.unshift(0, 0);  // index, deleteCount
     this.dataModel_.splice.apply(this.dataModel_, spliceArgs);
 
-    rescanDone();
+    if (opt_callback)
+      opt_callback();
   };
 
   FileManager.prototype.findListItem_ = function(event) {
     var node = event.srcElement;
     while (node) {
       if (node.tagName == 'LI')
         break;
       node = node.parentNode;
     }
 
@@ skipping 652 matching lines @@
           });
       }, onError);
 
       function onError(err) {
         console.log('Error while checking free space: ' + err);
         setTimeout(doCheck, 1000 * 60);
       }
     }
   }
 })();