Fenix: Ensure parent process triggers speculative connection when possible.

[fluffyemily]

Originally raised as bug against GeckoView.

Perhaps Fenix has already some speculative connection enabled. (and if so, just close this. I couldn't find such code immediately.)
But if not, it probably should have.

https://bugzilla.mozilla.org/show_bug.cgi?id=1383299 is where the stuff was added to desktop.

GeckoWebExecutor in GeckoView provides an API to create speculative connections that Fenix can implement.

[mcomella]

@fluffyemily In practice, what would an implementation of this look like? e.g. do we speculatively connect while the user types URL in the URL bar?

I'm not sure how to prioritize this yet.

[mcomella]

Triage from Christian: we already do speculative connections for applink. However, we can introduce this when typing in the URL bar – Fennec already does this and we could copy their implementation for a page load win.

[mcomella]

Adding group-triage: not sure if we have the cycles to address this short term but it could be a good page load win so consulting Fenix triage.

[csadilek]

See:
https://github.com/mozilla-mobile/android-components/issues/1912
https://searchfox.org/mozilla-esr68/source/mobile/android/base/java/org/mozilla/gecko/home/BrowserSearch.java#522-525
https://searchfox.org/mozilla-esr68/source/mobile/android/base/java/org/mozilla/gecko/home/BrowserSearch.java#623-627
https://searchfox.org/mozilla-esr68/source/mobile/android/chrome/content/browser.js#8029-8050

We will look into this in an upcoming A-C sprint. Marked for triage in A-C.

[acreskeyMoz]

FYI, I have data showing that the applink speculative connect that Fenix makes (via `RemoteWebNavigation.jsm) is very effective.

Compare fenix_intent, to fenix_intent_no_spec
https://docs.google.com/spreadsheets/d/133a2JzAw4nD6gWplm1X5m0ulbEX24ySgHPzh2mCEtc4/edit#gid=433931785&range=466:492

More discussion in this bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=1612575

[csadilek]

Fenix now (since Nightly 200303 18:01) triggers speculative connects when:

• An intent is received (this was working before)
• The URL is auto-completed in the toolbar, based on our shipped domain list and history (similar to Fennec)
• For top scored awesomebar suggestions for bookmarks, history, and search suggestions (also similar to Fennec)
• For URLs suggested from the clipboard

@acreskeyMoz ^^ I am closing the ticket here as we have https://bugzilla.mozilla.org/show_bug.cgi?id=1612575 to verify. Please re-open if needed / if we think this is not sufficient. Thanks!