function _getThemeManager(bClear) {
		var ThemeManager = sap.ui.require("sap/ui/core/theming/ThemeManager");
		if (!pThemeManager) {
			if (!ThemeManager) {
				pThemeManager = new Promise(function (resolve, reject) {
					sap.ui.require(["sap/ui/core/theming/ThemeManager"], function (ThemeManager) {
						resolve(ThemeManager);
					}, reject);
				});
			} else {
				pThemeManager = Promise.resolve(ThemeManager);
			}
		}
		// This is only used within initLibrary to reset flag themeLoaded synchronously in case
		// a theme for a new library will be loaded
		if (ThemeManager && bClear) {
			ThemeManager.reset();
		}
		return pThemeManager;
	}
Get the sap/ui/core/theming/ThemeManager on demand

@param {boolean} [bClear=false] Whether to reset the ThemeManager
@returns {Promise} The promise that resolves with the sap/ui/core/theming/ThemeManager class