Chrome Version: 71.0.3578.98 (Official Build) (64-bit)
OS: MacOS 10.14.1

What steps will reproduce the problem?
(1) Switch to "Dvorak-QWERTY-⌘" layout it MacOS keyboard layouts.
(2) Press "Ctrl+Tab" to switch to the next tab.
(3) Press "Shift+Ctrl+Tab" to switch to the previous tab.

What is the expected result?

Step (2) move to the next tab, step (3) should move to the previous tab.

What happens instead?

Both (2) and (3) move to the next tab; the "Shift" modifier is ignored.

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This is a recent regression in the past few months — until Chrome 69 my shortcuts were working as expected. See: https://productforums.google.com/forum/#!topic/chrome/a5eJmjddxlk.