The nudges/tips experiment needs to be able to open the urlbar view and show a tip without the user's interacting with the urlbar. i.e., it needs to be able to start an empty search so that its provider is called and can return a single tip result.

This is probably best implemented in mozilla-central as part of the browser.urlbar API. OTOH it may be a good idea to implement all new urlbar APIs in our experiment extensions, as experimental APIs, until they prove themselves over time to be useful in multiple extensions.

The core part of this is trivial, but the forceUserTyping complexity in is due to the fact that the nudges spec shows the go-arrow button in the urlbar instead of the dropdown arrow when the view is open and showing the tip [1]. If you call UrlbarInput.search with an empty string, the dropdown arrow will appear, and that is what we want when showing the history view, but not in this case.

[1] https://mozilla.invisionapp.com/share/S5SQCACBVAF#/screens/370460250_Search_Tips_Experiment

https://treeherder.mozilla.org/#/jobs?repo=try&revision=34071a1986e636c049aec99f17376a17bbf433e8

https://hg.mozilla.org/mozilla-central/rev/5b0cc1595568

Comment on attachment 9107107 [details]
Bug 1590461 - Add browser.urlbar.search() to the webextensions API

Beta/Release Uplift Approval Request

• User impact if declined: We'd like the option of running quantumbar experiments on 71 that require this patch (bug 1564506, bug 1568594). Otherwise we'd need to wait until 72.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): All this patch does is add a WebExtension API we can call from experiment add-ons. The API is only available to Mozilla add-ons. It has a test.
• String changes made/needed:

Comment on attachment 9107107 [details]
Bug 1590461 - Add browser.urlbar.search() to the webextensions API

Low risk, , uplift approved for 71 beta 9, thanks.

https://hg.mozilla.org/releases/mozilla-beta/rev/59d3f5ffaf6a