ChromeOS: fix user signin by alias.

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 bd7e4c9d5cd07922199d93b1dd0e1c0fba79cec1..feb021cbf82dad228fc766e7edd8d3e1ed1961fd 100644
--- a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
@@ -204,6 +204,11 @@ class GaiaScreenHandler : public BaseScreenHandler {
   // Returns temporary unused device Id.
   std::string GetTemporaryDeviceId();
 
+  // Returns user canonical e-mail. Finds already used account alias, if
+  // user has already signed in.
+  std::string GetCanonicalEmail(const std::string& authenticated_email,
+                                const std::string& gaia_id) const;
+
   // Current state of Gaia frame.
   FrameState frame_state_;