Bugfix for WebExtension

[STK913]

Can you approve this change to handle WebExtensions, please? The auth0-lock and auth0-js projects are affected by this change. I used auth0-chrome which is supposed to work for the extensions, but this library is not adapted and poses problems of ergonomics.
Thanks in advance.

[damieng]

I think we need more information as to exactly what is broken here. We need to be able to repro the issue first. Typically a PR like this is attached to an issue that gives the right context.

[STK913]

I created an example project here: https://github.com/STK913/WebExtensionForAuth0

Edit the AUTH0_CLIENT_ID and AUTH0_DOMAIN variables in variables.ts.
Download NPM packages: npm i
Since this is an Ionic/Angular project, you will need to run this command: npm install -g ionic
Then start the project: ionic serve
The project should be compiled and accessible from: http://localhost:8100
But what interests us is the extension, so go to the list of extensions in Google Chrome: chrome://extensions/
Display developer mode with the check box at the top right.
Load the unpackaged extension that corresponds to this folder: www
Get the extension ID from chrome://extensions/ to add it to the Auth0 application configuration:

• Add in "Allowed Callback URLs": chrome-extension://EXTENSION_ID/index.html
• Add in "Allowed Web Origins": chrome-extension://EXTENSION_ID
• Add in "Allowed Origins (CORS)": chrome-extension://EXTENSION_ID

Open the extension from the browser icon (next to the address bar).
Try to log in with your Auth0 credentials and you will see that the spinner is running in a loop because of the following error:
ERROR TypeError: Cannot read property 'protocol' of null
at Object.getOriginFromUrl (vendor.js:100277)

Modify directly www/vendor.js and apply the patch in the getLocationFromUrl method as I did in my commit (in 3 places).
Reinstall the extension again and you will be able to connect.

Ps: I also created a request here: auth0/auth0.js#1054

[stevehobbsdev]

Thanks for your contribution @STK913. For issues like this in the future we'd appreciate an issue first to discuss a potential fix, and move on from there.