anchor.diff:  
   import '../globals.dart';
   import '../service_extensions.dart';
  +import '../service_manager.dart' show ServiceExtensionState;
   import '../service_registrations.dart';
   import '../utils.dart';
   import 'analytics.dart' as ga;
  
positive.code:     serviceManager.serviceExtensionManager.hasServiceExtension(
          extensionName, (available) => selector.disabled = !available);
  
      _updateState();
    }
  
    final ServiceExtensionDescription extensionDescription;
  
negative.code:         ServiceExtensionButton(debugAllowBanner).button,
        ]),
      div(c: 'btn-group nowrap margin-left')
        ..add(TogglePlatformSelector().selector)
    ];
  }
  
  