UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Steps to reproduce the problem:
1. Load https://w3c.github.io/uievents/tools/key-event-viewer.html
2. Press Space, KeyB, KeyI, KeyM, KeyV, KeyY or Backslash with pressing Ctrl key on Windows. (I tested with Japanese keyboard layout.)

What is the expected behavior?
Those key combinations won't cause inputting text. Therefore, for conforming to UI Events, Chromium shouldn't dispatch keypress event for those key combinations.
https://w3c.github.io/uievents/#event-type-keypress
"If supported by a user agent, this event MUST be dispatched when a key is pressed down, if and only if that key normally produces a character value."

What went wrong?
keypress event is dispatched for those key combinations.

Did this work before? N/A 

Chrome version: 66.0.3359.181  Channel: stable
OS Version: 10.0
Flash Version: 

Firefox is now dispatching keypress events for them. However, Firefox will stop dispatching keypress events for non-printable key combinations soon.

However, note that Firefox won't stop dispatching keypress event for Enter, Shift + Enter and Ctrl + Enter since all existing browsers fire keypress event at least for those key combinations.  So, perhaps, any browsers shouldn't stop dispatching keypress event for them for backward compatibility. See <https://github.com/w3c/uievents/issues/183>.