message: fix: Check if XMLHttpRequest exists before using it
  Fixes loading raven in a JS dom environment
diff: @@ -1244,7 +1244,7 @@ Raven.prototype = {
  }
  if (autoBreadcrumbs.xhr && 'XMLHttpRequest' in _window) {
  - var xhrproto = XMLHttpRequest.prototype;
  + var xhrproto = _window.XMLHttpRequest && _window.XMLHttpRequest.prototype;
  fill(
  xhrproto,
  'open',
  