ash: Use SessionController instead of SessionStateDelegate

ash/common/system/tray/system_tray.cc

Index: ash/common/system/tray/system_tray.cc
diff --git a/ash/common/system/tray/system_tray.cc b/ash/common/system/tray/system_tray.cc
index c3c666cdca2165b456c1e08e5ab461daf245a8e1..a7d301ef762d9b76a8f5967bea23b75c76119b72 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -11,7 +11,7 @@
 #include "ash/common/key_event_watcher.h"
 #include "ash/common/login_status.h"
 #include "ash/common/material_design/material_design_controller.h"
-#include "ash/common/session/session_state_delegate.h"
+#include "ash/common/session/session_controller.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/system/chromeos/audio/tray_audio.h"
@@ -266,9 +266,8 @@ void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   const bool use_md = MaterialDesignController::IsSystemTrayMenuMaterial();
 
   // Create user items for each possible user.
-  int maximum_user_profiles = WmShell::Get()
-                                  ->GetSessionStateDelegate()
-                                  ->GetMaximumNumberOfLoggedInUsers();
+  const int maximum_user_profiles =
+      WmShell::Get()->session_controller()->GetMaximumNumberOfLoggedInUsers();
   for (int i = 0; i < maximum_user_profiles; i++)
     AddTrayItem(base::MakeUnique<TrayUser>(this, i));