Firefox overlay is seen opened even if Import Overlay is Cancelled.

chrome/browser/ui/views/importer/import_lock_dialog_view.h

Index: chrome/browser/ui/views/importer/import_lock_dialog_view.h
diff --git a/chrome/browser/ui/views/importer/import_lock_dialog_view.h b/chrome/browser/ui/views/importer/import_lock_dialog_view.h
index c69140a9c6a6691db284bbd791980c33cf77a3b9..65867c03ef7b4208188b07299fbd1403f429926c 100644
--- a/chrome/browser/ui/views/importer/import_lock_dialog_view.h
+++ b/chrome/browser/ui/views/importer/import_lock_dialog_view.h
@@ -22,6 +22,7 @@ class ImportLockDialogView : public views::DialogDelegateView {
  public:
   static void Show(gfx::NativeWindow parent,
                    const base::Callback<void(bool)>& callback);
+  static void Hide();
 
  private:
   explicit ImportLockDialogView(const base::Callback<void(bool)>& callback);
@@ -39,7 +40,6 @@ class ImportLockDialogView : public views::DialogDelegateView {
 
  private:
   views::Label* description_label_;
-
   // Called with the result of the dialog.
   base::Callback<void(bool)> callback_;