mash: Create system tray display and rotation lock items via delegate

ash/test/test_system_tray_delegate.h

Index: ash/test/test_system_tray_delegate.h
diff --git a/ash/test/test_system_tray_delegate.h b/ash/test/test_system_tray_delegate.h
index f83022fbdcb49429054d1d3d1e733677752e70ed..69ec1d5aa304210d36c50a9672b1d0474af32109 100644
--- a/ash/test/test_system_tray_delegate.h
+++ b/ash/test/test_system_tray_delegate.h
@@ -55,6 +55,10 @@ class TestSystemTrayDelegate : public DefaultSystemTrayDelegate {
   bool GetSessionStartTime(base::TimeTicks* session_start_time) override;
   bool GetSessionLengthLimit(base::TimeDelta* session_length_limit) override;
   void SignOut() override;
+  std::unique_ptr<SystemTrayItem> CreateDisplayTrayItem(
+      SystemTray* tray) override;
+  std::unique_ptr<SystemTrayItem> CreateRotationLockTrayItem(
+      SystemTray* tray) override;
 
  private:
   bool should_show_display_notification_;