Treat trusted contextmenu events as user activation.

[mustaqahmed]

The contextmenu event should be considered a user activation because it indicates that the user is interacting with the page.

Firefox already treats contextmenu events as user activation, hence allows web apps to use restricted APIs like navigator.vibrate(). In Chromium, we are on track to match the Firefox behavior because on mobile platforms, a web app should be able to mimic the native behavior of vibrating the device on long-press gestures (which fire contextmenu events). Here is a demo.

Note that on desktop, both Chromium and Firefox already treat contextmenu events as user activation (e.g. navigator.vibrate returns true in the above demo).

This PR is remotely related to #1903 (which is a work in progress in Chromium).

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/acknowledgements.html ( diff )
/interaction.html ( diff )

[RByers]

FWIW, this change makes sense to me as a small incremental step, largely separate from Mustaq's larger effort of rationalizing/simplifying this whole space.

[domenic]

This looks good to me, and brings the spec a bit more in line with existing browsers while we work on #1903. I think it's OK to forgo tests since testing user activation is not currently possible I believe (e.g. the pop-up blocker is always disabled in the web platform tests infra). I am hopeful that when we do #1903 we'll try to workaround those current testing limitations and have a larger set of tests for the whole space.

I'll give this another day to see if any other editors have thoughts, and then merge.

[annevk]

Is there an issue on testing being impossible? We should at least reference this so that when that issue gets resolved someone can pick up the slack...

[annevk]

Also, it appears this list was in lexicographical order. Seems worth preserving?

[annevk]

Finally, @mustaqahmed, you don't appear to be listed in the Acknowledgments section. Would you like to add yourself?

[mustaqahmed]

• Testing: Yes, testing is a pain today, and the blame goes to Make "triggered by user activation" match browser behavior #1903 again. I have added a wpt in my Chromium CL, ptal.

  • I am using navigator.vibrate to test activation because currently only Chrome and Firefox are expected to pass the test, and both of them support navigator.vibrate.
  • I originally hoped to use window.open instead because all browsers support it. However, diffs in popup blocker behavior turned out to be tricky.
  • I also tried Element.requestFullscreen() but didn't want to add prefix-specific switches.

• Event ordering: Done.

• Acknowledgements: Done.

[domenic]

Oh, neat. I know the pop-up blocker is disabled for web platform tests, but I didn't realize navigator.vibrate would go through a different code path.