Language settings: Fix Restart and Remove buttons shown at wrong times

chrome/browser/ui/webui/settings/languages_handler.h

 // Copyright (c) 2015 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_SETTINGS_LANGUAGES_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_LANGUAGES_HANDLER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
 
@@ skipping 14 matching lines @@
  public:
   explicit LanguagesHandler(content::WebUI* webui);
   ~LanguagesHandler() override;
 
   // SettingsPageUIHandler implementation.
   void RegisterMessages() override;
   void OnJavascriptAllowed() override {}
   void OnJavascriptDisallowed() override {}
 
  private:
-  // Changes the UI language, provided the user is allowed to do so.
-  void HandleSetUILanguage(const base::ListValue* args);
+  // Returns the prospective UI language. May not match the actual UI language,
+  // depending on the user's permissions and whether the language is substituted
+  // for another locale.
+  void HandleGetProspectiveUILanguage(const base::ListValue* args);
+
+  // Changes the preferred UI language, provided the user is allowed to do so.
+  // The actual UI language will not change until the next restart.
+  void HandleSetProspectiveUILanguage(const base::ListValue* args);
 
   Profile* profile_;  // Weak pointer.
 
   DISALLOW_COPY_AND_ASSIGN(LanguagesHandler);
 };
 
 }  // namespace settings
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_LANGUAGES_HANDLER_H_