[cros] Display emails of users are stored in a separate dictionary in Local State.

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

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
index 3730072ba728cefc2f11b0fe21d469e4b98f4e1f..91fbaae5681dea627453eefcf1773ca31c90f278 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
@@ -88,6 +88,10 @@ class SigninScreenHandlerDelegate {
   // Whether new user pod is available.
   virtual bool IsShowNewUser() const = 0;
 
+  // Sets the displayed email for the next login attempt. If it succeeds,
+  // user's displayed email value will be updated to |email|.
+  virtual void SetDisplayEmail(const std::string& email) = 0;
+
  protected:
   virtual ~SigninScreenHandlerDelegate() {}
 };