Verify features that are made "HTTPS-only" should be available on .onion sites as well

Firefox 49 is adding an isSecureContext attribute (https://developer.mozilla.org/en-US/docs/Web/API/Window/isSecureContext) we should make sure it returns true on .onion sites as well.

added component::applications/tor browser in Legacy / Trac owner::tbb-team in Legacy / Trac priority::medium in Legacy / Trac severity::normal in Legacy / Trac sponsor::27 in Legacy / Trac status::new in Legacy / Trac type::enhancement in Legacy / Trac labels

Can this be made opt-in? I don't really think Tor Browser should support any of the APIs that require Secure Contexts in the first place, even with HTTPS...

https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts

Trac:
Cc: N/A to yawning

Replying to yawning:

Can this be made opt-in? I don't really think Tor Browser should support any of the APIs that require Secure Contexts in the first place, even with HTTPS...

https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts

If it turns out to be the case that we think an API is to be disabled in an HTTPS context it won't be available on .onion sites either. This bug is more about stopping to bind isSecureContext to HTTPS.

Trac:
Sponsor: N/A to Sponsor27

mentioned in issue legacy/trac#27307 (moved)

mentioned in issue legacy/trac#27313 (moved)

mentioned in issue legacy/trac#28478 (moved)

mentioned in issue legacy/trac#29705 (moved)

mentioned in issue legacy/trac#31899 (moved)

moved from legacy/trac#21728 (moved)

added Feature label and removed 1 deleted label

removed 1 deleted label

added Icebox label

removed Icebox label

added Onion Services Roadmap::Future labels

This should be handled by our existing patch for #23247 (closed) ( 4d8c8d8f ) but we should verify.

removed Feature label

added Task label

changed title from Features that are made "HTTPS-only" should be available on .onion sites as well to Verify features that are made "HTTPS-only" should be available on .onion sites as well

added All Platforms label

added Apps::Type::Audit label

added Apps::Impact::Unknown label

added Apps::Impact::Medium label and removed Apps::Impact::Unknown label