Add IPFS and IPNS as safelisted schemes for registerProtocolHandler()

[javifernandez]

This commit updates the list of the safelisted schames that can
be handled by the registerProtocolHandler method to include IPFS
and IPNS schemes.

It also touches the current list to remove the bitcoin documentation
link, since it's already referenced on IANA's page for URI schemes.

• At least two implementers are interested (and none opposed):
  • Chrome
  • Firefox
• Tests are written and can be reviewed and commented upon at:
  • https://github.com/web-platform-tests/wpt/blob/master/html/webappapis/system-state-and-capabilities/the-navigator-object/protocol.tentative.https.html
• Implementation bugs are filed:
  • Chrome: https://bugs.chromium.org/p/chromium/issues/detail?id=651311
  • Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1631446
  • Safari: https://bugs.webkit.org/show_bug.cgi?id=73177 (registerProtocolHandler() not implemented)

(See WHATWG Working Mode: Changes for more details.)

---

/system-state.html ( diff )

[javifernandez]

With this PR I'm trying to unblock the discussion ongoing in the PR#5482 where we are trying to add several dweb protocols to the scheme safelist. During the discussion in the Firefox standard-position request, it was suggested to split up the PR to analyze each protocol independently, to address the concern of endorsing the technologies behind the schemes.

I guess we can assume Chrome's support given that a CL has already landed upstream with all these schemes safelisted.

Regarding Firefox, as mentioned before, there is an ongoing discussion in the standatd-postiion request submitted for the PR#5482, but perhaps we would need a new one specifically about IPFS and IPNS, as suggested by @dbaron

There is already a tentative test in the WPT repository, with all the protocols. We can merge it with the test defined for the current safelist schemes once this PR is merged.

[javifernandez]

cc @fred-wang who was the author of the original PR#5482,

[ben221199]

Why this isn't merged yet? 😕