Chrome Version: 63.0.3231.0

What steps will reproduce the problem?
(1) Start a local webserver, e.g. python SimpleHTTPServer
(2) Open a site with ES6 modules, e.g. see `index.html` + `moduleB.js`
(3) Alert is visible, modules work fine
(4) Open DevTools and refresh the inspected page

What is the expected result?
Page should refresh, finish loading, and alert once more.

What happens instead?
The loading spinner never stops spinning, DevTools' Network panel lists `moduleB.js` with status `(pending)`.


Notes:
- Repro might be a little flaky, sometimes toggling the 'Disable cache' in Network panel between refreshing might trigger this.
- While waiting, trying to open a second tab and repro usually causes the first tab to complete the request and show its alert.
 

Deleted: es6modulesTest.html 158 bytes

es6modulesTest.html 158 bytes View Download

Deleted: moduleB.js 43 bytes

moduleB.js 43 bytes View Download