Temporarily recreate implied Localhost permissions

[WizardCM]

Description

Allow requests to localhost from non-localhost pages. This is a common method of self-hosting tools for OBS.

Warning

This implementation uses OnShowPermissionPrompt, which is only called the first time such a request is made. If it was previously denied (even silently+automatically), that denial is saved permanently.
CEF does not currently provide methods to re-request or to clear/edit previously denied requests.

For the above reason, the handling of the permission prompt is only managed for the one permission, which is labelled as "Apps on device" in Chrome's Site Permissions page.

Motivation and Context

• Fixes Chrome Runtime regression: Local Network Access blocked #545 the right way

While adding disable-features=LocalNetworkAccessChecks would solve this, it has a wider scope of side effects than I'm comfortable with.

How Has This Been Tested?

Launch a HTTPS-hosted webpage that performs a fetch request to http://localhost:3000

Windows 10.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have read the contributing document.
• My code has been run through clang-format.
• My code follows the project's style guidelines
• My code is not on the master branch.
• My code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[PatTheMav]

This implementation uses OnShowPermissionPrompt, which is only called the first time such a request is made. If it was previously denied (even silently+automatically), that denial is saved permanently. CEF does not currently provide methods to re-request or to clear/edit previously denied requests.
For the above reason, the handling of the permission prompt is only managed for the one permission, which is labelled as "Apps on device" in Chrome's Site Permissions page.

Yeah that's unfortunately become a necessity because bad actors would otherwise just spam the request to coerce people into giving a site permissions they actually don't want to give

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So this is just a workaround to reinstate the behaviour of the prior CEF version until we can do proper permission management for docks and sources?

[WizardCM]

So this is just a workaround to reinstate the behaviour of the prior CEF version until we can do proper permission management for docks and sources?

Correct, the goal in a future OBS release is to provide a method for users to individually allow/deny these permission requests themselves, pending UX design by Warchamp. I'd like to also provide a nice UI for managing existing permissions, but as mentioned there is currently no CEF API we can pull from.

[RytoEX]

LGTM I will squash the commit.