window.onunhandledrejection = function()

in stackdriver-errors.js [83:89]


    window.onunhandledrejection = function(promiseRejectionEvent) {
      if (promiseRejectionEvent) {
        reporter.report(promiseRejectionEvent.reason).catch(noop);
      }
      oldPromiseRejectionHandler(promiseRejectionEvent);
      return true;
    };