ash: Merge LoginStatus update code path

ash/shell/content/client/shell_browser_main_parts.cc

Index: ash/shell/content/client/shell_browser_main_parts.cc
diff --git a/ash/shell/content/client/shell_browser_main_parts.cc b/ash/shell/content/client/shell_browser_main_parts.cc
index b61ace578a911b741cbeaf7587a17849109beef6..4a35215687cbe96fbf00b7c00452d4c80e684dba 100644
--- a/ash/shell/content/client/shell_browser_main_parts.cc
+++ b/ash/shell/content/client/shell_browser_main_parts.cc
@@ -140,9 +140,6 @@ void ShellBrowserMainParts::PreMainMessageLoopRun() {
           Shell::Get()->session_controller());
   example_session_controller_client_->Initialize();
 
-  ash::Shell::Get()->CreateShelfView();

[msw, 2017/04/05 00:15:47]

I guess this isn't needed because it's called by Shell::SessionStateChanged?
Maybe update the comment above (remove "before creating shelf")?

[xiyuan, 2017/04/05 22:29:07]

Yep. We no longer need to special handling this.

Comments updated.

-  ash::Shell::Get()->UpdateAfterLoginStatusChange(LoginStatus::USER);
-
   window_watcher_.reset(new ash::shell::WindowWatcher);
   display::Screen::GetScreen()->AddObserver(window_watcher_.get());