Add account_type into AccountId

chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h

Index: chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
index 21c5497864366899421685e24e333f870ba3b724..f276cd1577e2c7b00e6757daebe5ecce49588a9f 100644
--- a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
@@ -179,7 +179,8 @@ class GaiaScreenHandler : public BaseScreenHandler,
   // Returns user canonical e-mail. Finds already used account alias, if
   // user has already signed in.

[Andrew T Wilson (Slow), 2016/11/29 11:05:36]

Document what account_type is.

[Roman Sorokin (ftl), 2016/12/02 11:13:10]

Switched to enum class

   AccountId GetAccountId(const std::string& authenticated_email,
-                         const std::string& gaia_id) const;
+                         const std::string& gaia_id,
+                         const std::string& account_type) const;

[Andrew T Wilson (Slow), 2016/11/29 11:05:36]

Seems like most places are just passing an empty string as account_type. Should
we define a separate GetAccountIdWithType() or something like that, and leave
GetAccountId() alone? Would greatly shrink this patch.

[Alexander Alekseev, 2016/11/30 04:18:42]

Yes, it will. But I believe that people should always supply all the known
information. So I'd prefer the longer version.

On the other hand, call to "GetAccountId" is temporary for most of this patch
and will go away after most of chrome code will use it as user identifier.

 
   bool offline_login_is_active() const { return offline_login_is_active_; }
   void set_offline_login_is_active(bool offline_login_is_active) {