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

chrome/browser/ui/ash/system_tray_delegate_chromeos.h

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.h
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
index 64ba22a3e52a2ed4b8ceeb655674c4e94a2a9149..5341d0d9535af71cc5f8bf071835408cdd0e5901 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
@@ -98,6 +98,8 @@ class SystemTrayDelegateChromeOS
   void ShowDateSettings() override;
   void ShowSetTimeDialog() override;
   void ShowNetworkSettingsForGuid(const std::string& guid) override;
+  std::unique_ptr<ash::SystemTrayItem> CreateDisplayTrayItem(
+      ash::SystemTray* tray) override;
   void ShowDisplaySettings() override;
   void ShowPowerSettings() override;
   void ShowChromeSlow() override;