function getBrowserPerformance() {
    var performance = getGlobalObject().performance;
    if (!performance || !performance.now) {
        return undefined;
    }
    // Replace performance.timeOrigin with our own timeOrigin based on Date.now().
    //
    // This is a partial workaround for browsers reporting performance.timeOrigin such that performance.timeOrigin +
    // performance.now() gives a date arbitrarily in the past.
    //
    // Additionally, computing timeOrigin in this way fills the gap for browsers where performance.timeOrigin is
    // undefined.
    //
    // The assumption that performance.timeOrigin + performance.now() ~= Date.now() is flawed, but we depend on it to
    // interact with data coming out of performance entries.
    //
    // Note that despite recommendations against it in the spec, browsers implement the Performance API with a clock that
    // might stop when the computer is asleep (and perhaps under other circumstances). Such behavior causes
    // performance.timeOrigin + performance.now() to have an arbitrary skew over Date.now(). In laptop computers, we have
    // observed skews that can be as long as days, weeks or months.
    //
    // See https://github.com/getsentry/sentry-javascript/issues/2590.
    //
    // BUG: despite our best intentions, this workaround has its limitations. It mostly addresses timings of pageload
    // transactions, but ignores the skew built up over time that can aversely affect timestamps of navigation
    // transactions of long-lived web pages.
    var timeOrigin = Date.now() - performance.now();
    return {
        now: function () { return performance.now(); },
        timeOrigin: timeOrigin,
    };
}
Returns a wrapper around the native Performance API browser implementation, or undefined for browsers that do not
support the API.

Wrapping the native API works around differences in behavior from different browsers.