Fix open dialog not remembering last opened folder on drive

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 2904 matching lines @@
     if (selectAllCheckbox)
       this.updateSelectAllCheckboxState_(selectAllCheckbox);
   };
 
   FileManager.prototype.updateOkButton_ = function(event) {
     var selectable;
 
     if (this.dialogType_ == FileManager.DialogType.SELECT_FOLDER) {
       // In SELECT_FOLDER mode, we allow to select current directory
       // when nothing is selected.
-      selectable = this.selection.directoryCount <= 1 &&
-          this.selection.fileCount == 0;
+      selectable = this.selection &&
+                   this.selection.directoryCount <= 1 &&
+                   this.selection.fileCount == 0;
     } else if (this.dialogType_ == FileManager.DialogType.SELECT_OPEN_FILE) {
-      selectable = (this.isSelectionAvailable() &&
+      selectable = (this.selection &&
+                    this.isSelectionAvailable() &&
                     this.selection.directoryCount == 0 &&
                     this.selection.fileCount == 1);
     } else if (this.dialogType_ ==
                FileManager.DialogType.SELECT_OPEN_MULTI_FILE) {
-      selectable = (this.isSelectionAvailable() &&
+      selectable = (this.selection &&
+                    this.isSelectionAvailable() &&
                     this.selection.directoryCount == 0 &&
                     this.selection.fileCount >= 1);
     } else if (this.dialogType_ == FileManager.DialogType.SELECT_SAVEAS_FILE) {
       if (this.isOnReadonlyDirectory()) {
         selectable = false;
       } else {
         selectable = !!this.filenameInput_.value;
       }
     } else if (this.dialogType_ == FileManager.DialogType.FULL_PAGE) {
       // No "select" buttons on the full page UI.
@@ skipping 1186 matching lines @@
       this.defaultActionMenuItem_.taskId = taskItem.taskId;
     }
 
     var defaultActionSeparator =
         this.dialogDom_.querySelector('#default-action-separator');
 
     this.defaultActionMenuItem_.hidden = !taskItem;
     defaultActionSeparator.hidden = !taskItem;
   }
 })();