[Signin Error Dialog] (3/3) Added the triggering code

chrome/browser/ui/signin_view_controller.h

 // Copyright 2016 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.
 
 #ifndef CHROME_BROWSER_UI_SIGNIN_VIEW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_SIGNIN_VIEW_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/ui/profile_chooser_constants.h"
 
@@ skipping 16 matching lines @@
   static bool ShouldShowModalSigninForMode(profiles::BubbleViewMode mode);
 
   // Shows the signin flow as a tab modal dialog attached to |browser|'s active
   // web contents.
   // |access_point| indicates the access point used to open the Gaia sign in
   // page.
   void ShowModalSignin(profiles::BubbleViewMode mode,
                        Browser* browser,
                        signin_metrics::AccessPoint access_point);
   void ShowModalSyncConfirmationDialog(Browser* browser);
+  void ShowModalSigninErrorDialog(Browser* browser);
 
   // Closes the tab-modal signin flow previously shown using this
   // SigninViewController, if one exists. Does nothing otherwise.
   void CloseModalSignin();
 
   // Sets the height of the modal signin dialog.
   void SetModalSigninHeight(int height);
 
   // Notifies this object that it's |signin_view_controller_delegate_|
   // member has become invalid.
   void ResetModalSigninDelegate();
 
   SigninViewControllerDelegate* delegate() {
     return signin_view_controller_delegate_;
   }
 
  private:
   SigninViewControllerDelegate* signin_view_controller_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninViewController);
 };
 
 #endif  // CHROME_BROWSER_UI_SIGNIN_VIEW_CONTROLLER_H_