I'm implementing Request class in Chromium.
While I'm writing test codes like the following, I noticed a problem.

var baseRequest = new Request('test.html', {headers: {'X-Test': 'test'}});
var request = new Request(baseRequest, {mode: 'no-cors'});
console.log(request.headers.get('X-Test'))  // -> 'test'

This request.headers should not have 'X-Test' header, because the mode is no-cors and 'X-Test' is not a simple header.

http://fetch.spec.whatwg.org/#request-class
The Request(input, init) constructor must run these steps:
...
If r's request's mode is no CORS, run these substeps:

1. If r's request's method is not a simple method, throw a TypeError.
2. Set r's Headers object's guard to request-no-CORS.

I think we should remove non simple headers here.

Is my understanding correct?