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

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

 // Copyright 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.
 
 #include "chrome/browser/ui/webui/settings/languages_handler.h"
 
 #include "base/bind.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/web_ui.h"
 
-#if defined(OS_WIN)
+#if defined(OS_WIN) || defined(OS_CHROMEOS)
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/pref_names.h"
 #include "components/prefs/pref_service.h"
 #endif
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "components/user_manager/user_manager.h"
 #include "components/user_manager/user_type.h"
 #endif
 
 namespace settings {
 
 LanguagesHandler::LanguagesHandler(content::WebUI* webui)
     : profile_(Profile::FromWebUI(webui)) {
 }
 
 LanguagesHandler::~LanguagesHandler() {
 }
 
 void LanguagesHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback(
-      "setUILanguage",
-      base::Bind(&LanguagesHandler::HandleSetUILanguage,
+      "getProspectiveUILanguage",
+      base::Bind(&LanguagesHandler::HandleGetProspectiveUILanguage,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "setProspectiveUILanguage",
+      base::Bind(&LanguagesHandler::HandleSetProspectiveUILanguage,
                  base::Unretained(this)));
 }
 
-void LanguagesHandler::HandleSetUILanguage(const base::ListValue* args) {
+void LanguagesHandler::HandleGetProspectiveUILanguage(
+    const base::ListValue* args) {
+#if defined(OS_WIN) || defined(OS_CHROMEOS)
+  const base::Value* callback_id;
+  CHECK(args->Get(0, &callback_id));
+
+  AllowJavascript();
+
+  std::string locale;
+#if defined(OS_CHROMEOS)
+  // On Chrome OS, an individual profile may have a preferred locale.
+  locale = profile_->GetPrefs()->GetString(prefs::kApplicationLocale);
+#endif  // defined(OS_CHROMEOS)
+
+  if (locale.empty()) {
+    locale =
+        g_browser_process->local_state()->GetString(prefs::kApplicationLocale);
+  }
+
+  ResolveJavascriptCallback(*callback_id, base::StringValue(locale));
+#else
+  NOTREACHED() << "Attempting to get locale on unsupported platform";
+#endif  // defined(OS_WIN) || defined(OS_CHROMEOS)
+}
+
+void LanguagesHandler::HandleSetProspectiveUILanguage(
+    const base::ListValue* args) {
+  AllowJavascript();
   CHECK_EQ(1U, args->GetSize());
 
   std::string language_code;
   CHECK(args->GetString(0, &language_code));
 
 #if defined(OS_WIN)
   PrefService* prefs = g_browser_process->local_state();
   prefs->SetString(prefs::kApplicationLocale, language_code);
 #elif defined(OS_CHROMEOS)
   // Secondary users and public session users cannot change the locale.
   user_manager::UserManager* user_manager = user_manager::UserManager::Get();
   const user_manager::User* user =
       chromeos::ProfileHelper::Get()->GetUserByProfile(profile_);
   if (user &&
       user->GetAccountId() == user_manager->GetPrimaryUser()->GetAccountId() &&
       user->GetType() != user_manager::USER_TYPE_PUBLIC_ACCOUNT) {
     profile_->ChangeAppLocale(language_code,
                               Profile::APP_LOCALE_CHANGED_VIA_SETTINGS);
   }
 #else
   NOTREACHED() << "Attempting to set locale on unsupported platform";
 #endif
 }
 
 }  // namespace settings