Adding user into session doesn't generate login-prompt-visible.

chrome/browser/chromeos/login/webui_login_view.h

Index: chrome/browser/chromeos/login/webui_login_view.h
diff --git a/chrome/browser/chromeos/login/webui_login_view.h b/chrome/browser/chromeos/login/webui_login_view.h
index b7e36ac1eba783dd4c3071344c2973c1305be9f8..b1f48281be1bb4ac1aec015662060073d2996ff8 100644
--- a/chrome/browser/chromeos/login/webui_login_view.h
+++ b/chrome/browser/chromeos/login/webui_login_view.h
@@ -101,12 +101,12 @@ class WebUILoginView : public views::View,
 
   void set_is_hidden(bool hidden) { is_hidden_ = hidden; }
 
- protected:
-  // Let non-login derived classes suppress emission of this signal.
+  // Let suppress emission of this signal.
   void set_should_emit_login_prompt_visible(bool emit) {
     should_emit_login_prompt_visible_ = emit;
   }
 
+ protected:
   // Overridden from views::View:
   virtual void Layout() OVERRIDE;
   virtual void OnLocaleChanged() OVERRIDE;