Not blinking action tasks.

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.
 
 // Setting the src of an img to an empty string can crash the browser, so we
 // use an empty 1x1 gif instead.
 
 /**
  * FileManager constructor.
  *
@@ skipping 2224 matching lines @@
     };
 
     if (!selection.indexes.length) {
       this.updateCommonActionButtons_();
       this.updatePreviewPanelVisibility_();
       cr.dispatchSimpleEvent(this, 'selection-summarized');
       return;
     }
 
     this.previewSummary_.textContent = str('COMPUTING_SELECTION');
-    // Removing childrens of task buttons and preview thumbnails after simple
-    // event dispatched (see above). This can ensure a smooth disappearing
-    // animation when nothing is selected.
-    this.taskItems_.visible = false;
-    this.taskItems_.clear();
     removeChildren(this.previewThumbnails_);
 
     var fileCount = 0;
     var byteCount = 0;
     var pendingFiles = [];
     var thumbnailCount = 0;
 
     for (var i = 0; i < selection.indexes.length; i++) {
       var entry = this.directoryModel_.fileList.item(selection.indexes[i]);
       if (!entry)
@@ skipping 60 matching lines @@
       }
 
       if (pendingFiles.length) {
         cacheEntryDateAndSize(pendingFiles.pop(), cacheNextFile);
       } else {
         self.dispatchEvent(new cr.Event('selection-summarized'));
       }
     }
 
     if (this.dialogType_ == FileManager.DialogType.FULL_PAGE) {
-      this.taskItems_.clear();
       // Some internal tasks cannot be defined in terms of file patterns,
       // so we pass selection to check for them manually.
       if (selection.directoryCount == 0 && selection.fileCount > 0) {
         // Only files, not directories, are supported for external tasks.
         chrome.fileBrowserPrivate.getFileTasks(
             selection.urls,
             this.onTasksFound_.bind(this, selection));
       } else {
         // There may be internal tasks for directories.
         this.onTasksFound_(selection, []);
@@ skipping 195 matching lines @@
           task.iconUrl =
               chrome.extension.getURL('images/filetype_generic.png');
           task.title = str('INSTALL_CRX');
         }
       }
       this.renderTaskItem_(task);
       tasksCount++;
       if (defaultTask == null) defaultTask = task;
     }
 
-    this.taskItems_.visible = tasksCount > 0;
+    this.taskItems_.hidden = tasksCount == 0;
     if (tasksCount > 1) {
       // Duplicate default task in drop-down list.
       this.renderTaskItem_(defaultTask);
     }
 
     selection.tasksList = tasksList;
     if (selection.dispatchDefault) {
       // We got a request to dispatch the default task for the selection.
       selection.dispatchDefault = false;
       this.dispatchDefaultTask_(selection);
@@ skipping 1847 matching lines @@
 
     chrome.fileBrowserPrivate.setGDataPreferences(changeInfo);
 
     if (oldValue) {
       event.target.removeAttribute('checked');
     } else {
       event.target.setAttribute('checked', 'checked');
     }
   };
 })();