Android reftests run with apz.allow_zooming=false, but deployment has that pref set to true. Logic introduced in Bug 1504659 affects the way scrolling works on Android when that pref is false, and it causes several reftests to fail. Since the failures are not in deployment, the failing tests were disabled. This bug is tracking efforts to get those tests working again.

To be clear, the tests have not been disabled -- they have been marked as failing.

I've succeeded making the reftests in layout/reftest/bugs pass in bug 1520077. Now I think frame-reconstruction-scroll-clamping.html the only one test case we should care in this bug.

(In reply to Hiroyuki Ikezoe (:hiro) from comment #2)

I've succeeded making the reftests in layout/reftest/bugs pass in bug 1520077. Now I think frame-reconstruction-scroll-clamping.html the only one test case we should care in this bug.

There is still layout/reftests/bugs/1242172-2.html as well.

(The tests were only marked as failing in 66, so I'm marking earlier versions as unaffected.)

My patch series in bug 1517895 fixes frame-reconstruction-scroll-clamping.html.

(In reply to Botond Ballo [:botond] from comment #3)

(In reply to Hiroyuki Ikezoe (:hiro) from comment #2)

I've succeeded making the reftests in layout/reftest/bugs pass in bug 1520077. Now I think frame-reconstruction-scroll-clamping.html the only one test case we should care in this bug.

There is still layout/reftests/bugs/1242172-2.html as well.

I had to investigate this a bit since the test passes with patches for bug 1508177.
The test aims to check the vertical scrollbar on the root element is rendered properly, but it's not rendered on non-E10S (Fennec). The reason why the vertical scrollbar is not rendered is that nsIWidget::GetCompositionSize() in UpdateCompositionBoundsForRCDRSF returns a bit taller value than expected (the value on my environment is 1136px but it should be 1000px, the reftest canvas height).

The test has two square images which are laid out horizontal so that the content width is 2x greater than its height. So that with my patches for bug 1508177 it gets to fit the screen which means some amount of vertical regions become overflow scrollable area, thus the vertical scrollbar appears there. That's the reason why the test passes with my patches.

Anyways, I will add a meta viewport tag which is "width=device-width,initial-scale=1,minimum-scale=1" to avoid expanding the vertical scrollable region in bug 1508177.