Intent to ship: Visual Viewport API on Android

[Botond Ballo]

Hi everyone!

I would like to ship the Visual Viewport API [1] on Android. The
initial implementation [2] was done in Firefox 63 behind the pref
"dom.visualviewport.enabled" (see "Intent to Implement" thread [3]).
It has since seen bug fixes, polish, and expanded test coverage.

I intend to ship it on Android only for now. The API is primarily
useful in scenarios involving pinch-zooming, and we don't currently
support pinch-zooming on desktop. I intend to enable it on desktop
concurrently with support for pinch-zooming at a later date.

Target release: Firefox 68 or 69, depending on when the patches are
ready. If it doesn't make 68, I would like to get it into Fennec
68.1esr, as it's an important web compat feature.

Tracking bug for shipping: https://bugzilla.mozilla.org/show_bug.cgi?id=1512813

Status in other implementation:
Blink: Shipping since Chrome 61 [4]
Safari: Available in Preview version [5]

Web platform tests: The feature has good WPT coverage, with a mix of
automatic and manual tests. We are now [6] passing almost all tests on
Android; of the two remaining failures, one is a test harness
limitation [7], and the other is pending resolution of a spec issue
[8]. There are also a couple of tests which are not applicable to
Android because they involve reflowing zoom which Android does not
support.

Any thoughts / feedback is appreciated!

Thanks,
Botond

[1] https://github.com/WICG/visual-viewport/
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=1357785
[3] https://groups.google.com/d/topic/mozilla.dev.platform/gchNtWfv_bk/discussion
[4] https://www.chromestatus.com/feature/5737866978131968
[5] https://webkit.org/status/#feature-visual-viewport-api
[6] https://bugzilla.mozilla.org/show_bug.cgi?id=1477610
[7] https://bugzilla.mozilla.org/show_bug.cgi?id=1547827
[8] https://bugzilla.mozilla.org/show_bug.cgi?id=1543485

[David Burns]

There are a number of wpt that fail only in firefox[1]. Are we planning on
fixing those tests with this work?

David

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1546387

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[Botond Ballo]

On Thu, May 9, 2019 at 7:50 AM David Burns <dbu...@mozilla.com> wrote:
> There are a number of wpt that fail only in firefox. Are we planning on fixing those tests with this work?

We are, at least on Android. (On desktop, some of the tests need
desktop zooming, which we do not yet have, to pass.) A number of fixes
have landed [1] yesterday.

Is there a way to get a dashboard view similar to [2] with Android results?

Thanks,
Botond

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1477610
[2] https://jgraham.github.io/wptdash/?bugComponent=core%3A%3Alayout&paths=%2Fvisual-viewport&tab=Interop+Comparison

[David Burns]

Not yet as we are stabilising tests for gecko view but hopefully soon!

David

[James Graham]

On 10/05/2019 21:49, David Burns wrote:
> Not yet as we are stabilising tests for gecko view but hopefully soon!

That won't automatically work; we'd need to start uploading Android
results to wpt.fyi. Which is possible in one of two ways:

* Add Geckoview on Android to the TC configuration for wpt
* Start uploading results from m-c

The former has the advantage that all the upstream pushes will run kust
like for desktop, so the results will be directly comparable with other
browsers. The problem is that there may be implementation difficulties
connecting up taskcluster-github with the packet infrastructure for
running in the Android emulator. However if we do this it seems likely
we can also make Chrome Android work as a point of comparison.

The alternative where we just publish the results from m-c will end up
creating an entirely seperate set of Firefox-only data corresponding to
m-c pushes. That data won't be directly comparable against other
browsers, so although it's easier to do it's less useful.

I think getting android running upstream would be a good use of time and
resources, but it's likely to be a reasonable amount of work.

[Botond Ballo]

Hi,

> Target release: Firefox 68 or 69, depending on when the patches are
> ready. If it doesn't make 68, I would like to get it into Fennec
> 68.1esr, as it's an important web compat feature.

Just wanted to follow up and say that this did make 68.

There is one remaining Android wpt failure [1] which I hope to
investigate in the near future and uplift to 68 if possible.

Thanks,
Botond

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1552046