This is a revision to remove the functionality that was added over 3 or 4 previous revisions to ultimately use Powershell to set the default browser in MSIX builds. On Windows with a new feature enabled by Microsoft, this results in the HTTP and HTTPS handler being reset to Edge, which is a terrible experience.
Since there's no solve, this is rolling that all back. Done as one set of changes here because it's all deleted code except for one line, a rollback isn't clean, and it would change the Javascript side to be non-async again, which isn't necessary.
This will effectively be reopening Bug 1818418 - Allow to use Windows UserChoice default mechanisms for MSIX packages. All of the bugs created in between were side effects of that change / fix.
I will not reopen that bug because we don't plan to fix it. Microsoft is rolling out new changes that explicitly disallow that mechanism. When it hits 100%, it won't work on any build type (MSIX or not).
Differential Revision: https://phabricator.services.mozilla.com/D197747
cc78d71761