UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36

Steps to reproduce the problem:
1. Grab a Linux system. Lubuntu 18.04 works.
2. Grab a mouse with horizontal scroll. Mine is Logitech MX Master 2S.
3. Open a page that has both horizontal and vertical scroll, so you can test it. Also open some other application (such as Inkscape and Gimp), just for comparison purposes.

Scenario 1: Natural Scrolling is DISABLED

Run: xinput set-prop 'pointer:MX Master 2S' 'libinput Natural Scrolling Enabled' 0

Now try to scroll.
Moving your finger down moves the scrollbar down and the content up.
Moving the finger right moves the scrollbar right and the content left.
That's normal, that's expected.

Scenario 2: Natural Scrolling is ENABLED

Run: xinput set-prop 'pointer:MX Master 2S' 'libinput Natural Scrolling Enabled' 1

Now try to scroll.
Moving your finger down moves the content down and the scrollbar up. (correct)
Moving the finger right moves the content LEFT and the scrollbar RIGHT. (incorrect)
However, it works correctly in other applications (such as Inkscape and Gimp).

What is the expected behavior?

What went wrong?
When Natural Scrolling is enabled in libinput, vertical scrolling works correctly; but horizontal scrolling is reversed.

This seems to affect Chrome, VLC, LibreOffice.
This does not affect Firefox, Gimp, Inkscape, Qt Designer 4.8.7.

Did this work before? N/A 

Chrome version: 70.0.3538.110  Channel: stable
OS Version: Ubuntu 18.04
Flash Version: