In case of search add "Searching..." string to the spinner in the center.

chrome/browser/resources/file_manager/js/file_manager.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.
 
 /**
  * FileManager constructor.
  *
  * FileManager objects encapsulate the functionality of the file selector
  * dialogs, as well as the full screen file manager application (though the
  * latter is not yet implemented).
@@ skipping 591 matching lines @@
     this.previewPanel_ = this.dialogDom_.querySelector('.preview-panel');
     this.previewSummary_ = this.dialogDom_.querySelector('.preview-summary');
     this.filenameInput_ = this.dialogDom_.querySelector(
         '#filename-input-box input');
     this.taskItems_ = this.dialogDom_.querySelector('#tasks');
     this.okButton_ = this.dialogDom_.querySelector('.ok');
     this.cancelButton_ = this.dialogDom_.querySelector('.cancel');
     this.deleteButton_ = this.dialogDom_.querySelector('#delete-button');
     this.table_ = this.dialogDom_.querySelector('.detail-table');
     this.grid_ = this.dialogDom_.querySelector('.thumbnail-grid');
-    this.spinner_ = this.dialogDom_.querySelector('.spinner');
+    this.spinner_ = this.dialogDom_.querySelector('#spinner-with-text');
     this.showSpinner_(false);
     this.butter_ = this.dialogDom_.querySelector('.butter-bar');
     this.unmountedPanel_ = this.dialogDom_.querySelector('#unmounted-panel');
 
     this.breadcrumbs_ = new BreadcrumbsController(
          this.dialogDom_.querySelector('#dir-breadcrumbs'));
     this.breadcrumbs_.addEventListener(
          'pathclick', this.onBreadcrumbClick_.bind(this));
     this.searchBreadcrumbs_ = new BreadcrumbsController(
          this.dialogDom_.querySelector('#search-breadcrumbs'));
@@ skipping 2687 matching lines @@
   };
 
   FileManager.prototype.showSpinnerLater_ = function() {
     this.cancelSpinnerTimeout_();
     this.showSpinnerTimeout_ =
         setTimeout(this.showSpinner_.bind(this, true), 500);
   };
 
   FileManager.prototype.showSpinner_ = function(on) {
     this.cancelSpinnerTimeout_();
-    this.spinner_.style.display = on ? '' : 'none';
+    if (on) {
+      this.spinner_.textContent =
+          this.directoryModel_.isSearching() ? str('SEARCH_SPINNER') : '';
+      this.spinner_.style.display = '';
+    } else {
+      this.spinner_.style.display = 'none';
+    }
   };
 
   FileManager.prototype.onNewFolderCommand_ = function(event) {
     var defaultName = str('DEFAULT_NEW_FOLDER_NAME');
 
     // Find a name that doesn't exist in the data model.
     var files = this.directoryModel_.getFileList();
     var hash = {};
     for (var i = 0; i < files.length; i++) {
       var name = files.item(i).name;
@@ skipping 893 matching lines @@
     }
 
     var defaultActionSeparator =
         this.dialogDom_.querySelector('#default-action-separator');
 
     this.defaultActionMenuItem_.hidden = !taskItem;
     defaultActionSeparator.hidden = !taskItem;
   }
 })();