Re-reland: 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 4c3106f4ea53d9c2c88e9621388f48759c117e2c..18ef49212d5389a8bc4f173bfc94a45b050e0732 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -272,11 +272,6 @@ 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();