[ChromeOS] Expose keyboard remapping to signin screen.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h

 // Copyright (c) 2013 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_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 252 matching lines @@
                               OobeScreen new_screen) override;
 
   void SetFocusPODCallbackForTesting(base::Closure callback);
 
   // To avoid spurious error messages on flaky networks, the offline message is
   // only shown if the network is offline for a threshold number of seconds.
   // This method reduces the threshold to zero, allowing the offline message to
   // show instantaneously in tests.
   void ZeroOfflineTimeoutForTesting();
 
+  const AccountId& focused_pod_account_id() {

[xiyuan, 2017/02/22 17:40:18]

nit: Make it a const method
i.e.
  const AccountId& focused_pod_account_id() const {

[xdai1, 2017/02/22 18:36:16]

Removed this function according to alemate@'s suggestion.

+    return *focused_pod_account_id_.get();

[xiyuan, 2017/02/22 17:40:18]

What if |focused_pod_account_id_| holds nullptr and does not own anything?

+  }
+
  private:
   enum UIState {
     UI_STATE_UNKNOWN = 0,
     UI_STATE_GAIA_SIGNIN,
     UI_STATE_ACCOUNT_PICKER,
   };
 
   friend class GaiaScreenHandler;
   friend class ReportDnsCacheClearedOnUIThread;
   friend class SupervisedUserCreationScreenHandler;
@@ skipping 247 matching lines @@
   std::unique_ptr<AccountId> focused_pod_account_id_;
 
   base::WeakPtrFactory<SigninScreenHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_