Implement oauth token external handler checking.

chrome/browser/chromeos/login/ui/login_display_host_impl.h

Index: chrome/browser/chromeos/login/ui/login_display_host_impl.h
diff --git a/chrome/browser/chromeos/login/ui/login_display_host_impl.h b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
index 00624fda6e0c9493b344a5cff203117c5e6931d2..1a18b87e991feae53a36d6eac4dddec7c1182555 100644
--- a/chrome/browser/chromeos/login/ui/login_display_host_impl.h
+++ b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
@@ -15,6 +15,7 @@
 #include "chrome/browser/chromeos/login/app_launch_controller.h"
 #include "chrome/browser/chromeos/login/auth/auth_prewarmer.h"
 #include "chrome/browser/chromeos/login/existing_user_controller.h"
+#include "chrome/browser/chromeos/login/signin/token_handler_util.h"
 #include "chrome/browser/chromeos/login/signin_screen_controller.h"
 #include "chrome/browser/chromeos/login/ui/login_display.h"
 #include "chrome/browser/chromeos/login/ui/login_display_host.h"
@@ -196,6 +197,10 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   // Called when login-prompt-visible signal is caught.
   void OnLoginPromptVisible();
 
+  // Called when user oauth token handler check is completed.
+  void OnTokenHandlerChecked(const user_manager::UserID& user_id,
+                             TokenHandlerUtil::TokenHandleStatus token_status);
+
   // Used to calculate position of the screens and background.
   gfx::Rect background_bounds_;
 
@@ -288,6 +293,9 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   // Handles special keys for keyboard driven oobe.
   scoped_ptr<KeyboardDrivenOobeKeyHandler> keyboard_driven_oobe_key_handler_;
 
+  // Handles token handle operations.
+  scoped_ptr<TokenHandlerUtil> token_handler_util_;
+
   FinalizeAnimationType finalize_animation_type_;
 
   // Time when login prompt visible signal is received. Used for