If user profile doesn't contain language setting, default to his Google account settings.

chrome/browser/chromeos/login/user_manager.h

Index: chrome/browser/chromeos/login/user_manager.h
diff --git a/chrome/browser/chromeos/login/user_manager.h b/chrome/browser/chromeos/login/user_manager.h
index 08b030002c5710609e0e53e8a1a44be58ce1b091..a126932ef050f6146d7e7b707aad70db9355bf65 100644
--- a/chrome/browser/chromeos/login/user_manager.h
+++ b/chrome/browser/chromeos/login/user_manager.h
@@ -199,6 +199,11 @@ class UserManager {
   virtual const User* GetActiveUser() const = 0;
   virtual User* GetActiveUser() = 0;
 
+  // Returns primary user. There could be multiple users logged in at the
+  // same time, but only the first one defines locale and other login session
+  // parameters.
+  virtual const User* GetPrimaryUser() const = 0;
+
   // Saves user's oauth token status in local state preferences.
   virtual void SaveUserOAuthStatus(
       const std::string& username,
@@ -209,6 +214,11 @@ class UserManager {
   virtual void SaveUserDisplayName(const std::string& username,
                                    const string16& display_name) = 0;
 
+  // Updates data upon User Account download.
+  virtual void UpdateUserAccountData(const std::string& username,
+                                     const string16& display_name,
+                                     const std::string& locale) = 0;
+
   // Returns the display name for user |username| if it is known (was
   // previously set by a |SaveUserDisplayName| call).
   // Otherwise, returns an empty string.