chromeos: Fix shelf appearing at login screen under mash

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 66417d344e5c331923b82e065a882be2a23c9ffd..d9ee2f269362c2cf2bebf99e3d0826ae692af6a9 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -276,11 +276,6 @@ void Shell::OnLoginStateChanged(LoginStatus status) {
     observer.OnLoginStateChanged(status);
 }
 
-void Shell::OnLoginUserProfilePrepared() {
-  wm_shell_->CreateShelf();
-  CreateKeyboard();
-}
-
 void Shell::OnAppTerminating() {
   for (auto& observer : *wm_shell_->shell_observers())
     observer.OnAppTerminating();