Bug: Address Widget doesn't show correct URL on redirects

[cookiengineer]

The Address Widget doesn't show the correct URL when the iframe load leads to a redirect.

In order to fix this, the Webview Backdrop must include a method that will re-set (override?) the Tab's URL and change the history accordingly. Currently, inside the iframe based UI, it's not possible to detect a redirect otherwise.

On the server-side it's implemented correctly already, but this is a necessary hack that cannot be avoided.

In the on('load', () => {}) callback:

• Validate that the loaded URL is the actual rendered Tab's URL (this.window.location.href must be parsed as if it were an src attribute)
• If the URL isn't the same as it were before the load (the cached this.url attribute), modify the Tab's history without triggering a refresh event on the Browser.

[cookiengineer]

As of 9772e4a this has been implemented.

Important Architecture Notes:

There's no event on the iframe that can be listened to in order to trace a redirect from the server-side. In order to detect redirects, the Webview Backdrop now has on the iframe's load event a mechanism that reparses the iframe window.location.pathname + window.location.search in order to find out where exactly the iframe currently leads to.

If there was a redirect detected, the Webview updates the current BROWSER.tab's history without emitting a potential event cycle, and updates both the Address and Mode widgets.

This leads to a Tab History change (which is intended, as it will always show the correct URL in the Address Bar), and therefore the Error Pages can simply call the BROWSER.back() method after successful modifications.