Extracted this out of #5649
This commit was created with the following commands:
```
find . -iname "*.webidl" -type f -print0 | xargs -0 sed -i '' 's/http:\(.*\)whatwg.org/https:\1whatwg.org/g'
```
```
find . -iname "*.rs" -type f -print0 | xargs -0 sed -i '' 's/http:\(.*\)whatwg.org/https:\1whatwg.org/g'
```
Source-Repo: https://github.com/servo/servo
Source-Revision: 4997d3a112354a407365fede1ab1944834a2e13c
Because of #2122 I cannot write test for this right now because it will be failing randomly due to that iframe issue. However, if it doesn't fail due to that issue a test like this:
```html
<html>
<head>
<meta charset="utf8" />
<script src="harness.js"></script>
<title>Iframe contentDocument test.</title>
</head>
<body>
<iframe src="test_iframe_contentDocument_inner.html" id="iframe"></iframe>
<script>
waitForExplicitFinish();
var timeout = 100;
var iframe = document.getElementById('iframe');
function test_contentWindow() {
if (!iframe.contentWindow) {
// Iframe not loaded yet, try again.
// No load event for iframe, insert bug number here.
setTimeout(test_contentWindow, timeout);
return;
}
is(iframe.contentDocument.getElementById('test').textContent, 'value');
finish();
}
test_contentWindow();
</script>
</body>
</html>
```
where inner is simply:
```html
<html><body><div id="test">value</div></body></html>
```
passes.
I have added `SameOrigin` method to the `UrlHelper`. I wanted to reuse it in [`constellation.rs` same_script check](f0184a2d01/components/compositing/constellation.rs (L625)) but I it didn't want to compile saying
```
error: unresolved import `dom::urlhelper::UrlHelper`. Maybe a missing `extern crate dom`?
```
So I didn't include it in this PR for now.
There is more discussion about the cross origin iframes in [another issue](https://github.com/servo/servo/issues/3939). In this PR I just added same origin check.
Source-Repo: https://github.com/servo/servo
Source-Revision: 85a2f0b66a32cfd6022b3e6cec6ec06f3b59baf1
