UserAgent: Mozilla/5.0 (X11; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0

Steps to reproduce the problem:
1. Start Chromium
2. Navigate to the "Pointer lock demo" at https://mdn.github.io/dom-examples/pointer-lock/
3. Move the chromium window so that the pointer lock demo widget is partially off-screen (consider putting it partially off the right side of the screen, as problematic behavior is different depending on which edge of the screen is overlapped, and the problem is simplest to observe in this case)
4. Click on the pointer lock widget to enter pointer lock mode
5. Move the mouse so that the red ball "wraps" (as it normally does) around the sides of the widget several times. If you move it far enough in the right direction, it will "catch" as though the mouse cursor is stopping at the edge of the screen.

What is the expected behavior?
Expected behavior can be observed when the pointer lock demo widget does not overlap the edge of the screen.

Expected behavior is that it the red dot in the pointer lock demo widget will move freely with mouse input, wrapping around the edges of the widget.

What went wrong?
Mouse movement information passed to the client was not correct, causing the program to behave non-nonsensically.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 70.0.3507.0 (Developer Build) (64-bit)  Channel: n/a
OS Version: Debian Stretch (stable)
Flash Version: 

Thank you for your attention to this issue. You are wonderful.