Chrome Version: ToT
OS: Android phone

What steps will reproduce the problem?
(1) Use an Android phone (tablets are excluded)
(2) Use Chrome >= 60.0.3111.0
(3) Enable chrome://flags/#video-rotate-to-fullscreen (and leave chrome://flags/#video-fullscreen-orientation-lock enabled)
(4) Visit a page with native video controls, e.g. https://mounirlamouri.github.io/sandbox/media/dynamic-controls.html
(5) Make sure Android Quick Settings > Auto-rotate is enabled
(6) Hold the phone in portrait-primary orientation
(7) Press fullscreen on the video. The screen should become locked to landscape and hence show as landscape-primary
(8) Rotate the phone from portrait-primary to landscape-secondary (i.e. the opposite orientation to the one it got locked to)

What is the expected result?

The screen orientation should change directly from fullscreen landscape-primary to fullscreen landscape-secondary (without going via any portrait orientations or leaving fullscreen).

What happens instead?

It depends on the exact timing between pressing fullscreen and rotating the device, and perhaps also on the speed at which the device is rotated. But two failure modes sometimes occur:
(a) screen orientation changes from fullscreen landscape-primary to inline portrait-primary, before then continuing to fullscreen landscape-secondary
(b) screen orientation changes from fullscreen landscape-primary to inline landscape-secondary