message: Support sending the current theme to widgets
  This is a namespaced variable because some clients may not be able to support themes, or may have varying definitions of what "light" means. Widgets are recommended to opt for per-client checks, or accept that some clients may differ.
diff: @@ -27,6 +27,7 @@ import ScalarAuthClient from '../../../ScalarAuthClient';
  import ScalarMessaging from '../../../ScalarMessaging';
  import { _t } from '../../../languageHandler';
  import WidgetUtils from '../../../WidgetUtils';
  +import SettingsStore from "../../../settings/SettingsStore";
  // The maximum number of widgets that can be added in a room
  const MAX_WIDGETS = 2;
  @@ -131,6 +132,9 @@ module.exports = React.createClass({
  '$matrix_room_id': this.props.room.roomId,
  '$matrix_display_name': user ? user.displayName : this.props.userId,
  '$matrix_avatar_url': user ? MatrixClientPeg.get().mxcUrlToHttp(user.avatarUrl) : '',
  +
  + // Namespaced for Riot
  + '$riot_theme': SettingsStore.getValue("theme"),
  };
  app.id = appId;
  