Referrer should be parameter, not extra header

[schelkun]

If you look at this line, we trying to get referrer from extraHTTPHeaders:
https://github.com/GoogleChrome/puppeteer/blob/master/lib/Page.js#L565

So, at this code example I forced to clear extra headers for proper resources loading:

await page.setExtraHTTPHeaders({
  referer: 'https://example.com/'
});

await page.goto('https://github.com/');

await page.setExtraHTTPHeaders({});

This is really bad way to set referrer, because even in CDP referrer is specified as a parameter, not header. This is not even funny!
https://github.com/GoogleChrome/puppeteer/blob/master/lib/Page.js#L601

While I'm trying to clear headers after navigation with empty object, page will load resources (like CSS and scripts, images) with a wrong referrer!

Try to set extra header referer on your page and load image, and you will see amazing wrong referer:

So wee need smth like this:

• referrer as a optional parameter at goto, in this case method will ignore headers referer check
• referrer as a parameter only (best way)

Now I'm forced to rewrite goto method a little, can we fix it?

[aslushnikov]

Fair. We should add referer to the navigation options and make it override the one
specified via extra http headers.

await page.goto('https://google.com', {
  referer: 'https://example.com'
});