ChromeOS: switch UI language before apps are loaded.

chrome/browser/chromeos/login/session/user_session_manager.cc

Index: chrome/browser/chromeos/login/session/user_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/user_session_manager.cc b/chrome/browser/chromeos/login/session/user_session_manager.cc
index 871233e03287e1aa36b5093627814797f1ce5484..9b97e9f7b7e4bb8d0b48f94fce19c974e687aae0 100644
--- a/chrome/browser/chromeos/login/session/user_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/user_session_manager.cc
@@ -15,6 +15,7 @@
 #include "base/prefs/pref_member.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
+#include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
@@ -280,6 +281,43 @@ void LogCustomSwitches(const std::set<std::string>& switches) {
   }
 }
 
+// Wait until language is switched.
+class LocalePreferenceRespectedWaiter
+    : public base::SupportsWeakPtr<LocalePreferenceRespectedWaiter> {
+ public:
+  LocalePreferenceRespectedWaiter() : done_(false) {}
+
+  locale_util::SwitchLanguageCallback Callback(
+      const locale_util::SwitchLanguageCallback& callback) {
+    return base::Bind(&LocalePreferenceRespectedWaiter::OnLanguageSwitched,
+                      AsWeakPtr(), callback);
+  }
+
+  void RunUntilLocaleSet(void) {
+    if (done_)
+      return;
+
+    base::MessageLoop::ScopedNestableTaskAllower allow(
+        base::MessageLoop::current());
+
+    run_loop_.Run();
+  }
+
+ private:
+  void OnLanguageSwitched(const locale_util::SwitchLanguageCallback& callback,
+                          const locale_util::LanguageSwitchResult& result) {
+    done_ = true;
+    run_loop_.Quit();
+
+    callback.Run(result);
+  }
+
+  base::RunLoop run_loop_;
+  bool done_;
+
+  DISALLOW_COPY_AND_ASSIGN(LocalePreferenceRespectedWaiter);
+};
+
 }  // namespace
 
 UserSessionManagerDelegate::~UserSessionManagerDelegate() {
@@ -1556,7 +1594,8 @@ void UserSessionManager::DoBrowserLaunchInternal(Profile* profile,
     RespectLocalePreferenceWrapper(
         profile,
         base::Bind(&UserSessionManager::DoBrowserLaunchInternal, AsWeakPtr(),
-                   profile, login_host, true /* locale_pref_checked */));
+                   profile, login_host, true /* locale_pref_checked */),
+        false /* synchronous */);
     return;
   }
 
@@ -1607,19 +1646,29 @@ void UserSessionManager::DoBrowserLaunchInternal(Profile* profile,
 
 void UserSessionManager::RespectLocalePreferenceWrapper(
     Profile* profile,
-    const base::Closure& callback) {
+    const base::Closure& callback,
+    bool synchronous) {
   if (browser_shutdown::IsTryingToQuit())
     return;
 
   const user_manager::User* const user =
       ProfileHelper::Get()->GetUserByProfile(profile);
+
+  LocalePreferenceRespectedWaiter waiter;
+
   locale_util::SwitchLanguageCallback locale_switched_callback(base::Bind(
       &UserSessionManager::RunCallbackOnLocaleLoaded, callback,
       base::Owned(new InputEventsBlocker)));  // Block UI events until
                                               // the ResourceBundle is
                                               // reloaded.
-  if (!RespectLocalePreference(profile, user, locale_switched_callback))
+  if (synchronous)
+    locale_switched_callback = waiter.Callback(locale_switched_callback);
+
+  if (!RespectLocalePreference(profile, user, locale_switched_callback)) {
     callback.Run();
+  } else if (synchronous) {
+    waiter.RunUntilLocaleSet();
+  }
 }
 
 // static