Reuse FileTasks when entries are not changed.

ui/file_manager/file_manager/foreground/js/file_tasks.js

Index: ui/file_manager/file_manager/foreground/js/file_tasks.js
diff --git a/ui/file_manager/file_manager/foreground/js/file_tasks.js b/ui/file_manager/file_manager/foreground/js/file_tasks.js
index d40eb3366139c3ff831053a90e7370620c9946e6..3fc916d586a81e6b8547951c55cce882f1722a2e 100644
--- a/ui/file_manager/file_manager/foreground/js/file_tasks.js
+++ b/ui/file_manager/file_manager/foreground/js/file_tasks.js
@@ -68,6 +68,15 @@ function FileTasks(volumeManager, metadataModel, directoryModel, ui, entries,
   this.defaultTask_ = defaultTask;
 };
 
+FileTasks.prototype = {
+  /**
+   * @return {!Array<!Entry>}
+   */
+  get entries() {
+    return this.entries_;
+  }
+};
+
 /**
  * The app ID of the video player app.
  * @const