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

chrome/browser/profiles/profile_impl.h

Index: chrome/browser/profiles/profile_impl.h
diff --git a/chrome/browser/profiles/profile_impl.h b/chrome/browser/profiles/profile_impl.h
index 544091ec4216fe2434f10d008287ce8e91a7226b..5dad4a087f34444c0591aaedbef139d3c6cf2679 100644
--- a/chrome/browser/profiles/profile_impl.h
+++ b/chrome/browser/profiles/profile_impl.h
@@ -128,9 +128,12 @@ class ProfileImpl : public Profile {
 #if defined(OS_CHROMEOS)
   virtual void ChangeAppLocale(const std::string& locale,
                                AppLocaleChangedVia) OVERRIDE;
+  virtual void MarkCreated() OVERRIDE;
   virtual void OnLogin() OVERRIDE;
   virtual void SetupChromeOSEnterpriseExtensionObserver() OVERRIDE;
   virtual void InitChromeOSPreferences() OVERRIDE;
+  virtual void RespectLocalePreference() OVERRIDE;
+  virtual void SetGPlusProfileLocale(const std::string& gplus_locale) OVERRIDE;
 #endif  // defined(OS_CHROMEOS)
 
   virtual PrefProxyConfigTracker* GetProxyConfigTracker() OVERRIDE;
@@ -190,6 +193,9 @@ class ProfileImpl : public Profile {
   void GetCacheParameters(bool is_media_context,
                           base::FilePath* cache_path,
                           int* max_size);
+#if defined(OS_CHROMEOS)

[sail, 2013/08/23 17:08:48]

I really dislike adding new ifdefs to the code. The best way to add new platform
specific code is to have it in a platform specific file. Something like:
  my_profile_locale_cros.cc

[Alexander Alekseev, 2013/09/06 19:52:08]

Done.

+  void ChangeAppLocaleWnenEmpty(const std::string& new_locale);
+#endif
 
   PrefProxyConfigTracker* CreateProxyConfigTracker();
 
@@ -250,6 +256,9 @@ class ProfileImpl : public Profile {
       chromeos_enterprise_extension_observer_;
 
   scoped_ptr<chromeos::LocaleChangeGuard> locale_change_guard_;
+
+  bool is_created_;
+  scoped_ptr<std::string> gplus_locale_;
 #endif
 
   scoped_ptr<PrefProxyConfigTracker> pref_proxy_config_tracker_;