Move more from WmShell to Shell

ash/common/wm/overview/window_selector_controller.cc

Index: ash/common/wm/overview/window_selector_controller.cc
diff --git a/ash/common/wm/overview/window_selector_controller.cc b/ash/common/wm/overview/window_selector_controller.cc
index 9c49e07d539c7aa1d91bc8ab97dccb602a3a3be4..95f6f31f59763cbdf9f89747ae52b9ea9e2cd840 100644
--- a/ash/common/wm/overview/window_selector_controller.cc
+++ b/ash/common/wm/overview/window_selector_controller.cc
@@ -35,7 +35,8 @@ bool WindowSelectorController::CanSelect() {
   // open or running in kiosk app session.
   WmShell* wm_shell = WmShell::Get();
   SessionController* session_controller = wm_shell->session_controller();
-  SystemTrayDelegate* system_tray_delegate = wm_shell->system_tray_delegate();
+  SystemTrayDelegate* system_tray_delegate =
+      Shell::Get()->system_tray_delegate();
   return session_controller->IsActiveUserSessionStarted() &&
          !session_controller->IsScreenLocked() &&
          !wm_shell->IsSystemModalWindowOpen() && !wm_shell->IsPinned() &&