Chrome Version: M67+
OS: Linux

What steps will reproduce the problem?
(1) Enable  #top-chrome-md = refresh, #secondary-ui-md = enabled and #enable-autofill-native-dropdown-views = enabled
(2) Navigate to https://rsolomakhin.github.io/autofill and click on a field that is close to the bottom boundary of the window.
(3) The dropdown is constrained on the window on Linux, whereas it's not on Windows.

What is the expected result?

The dropdown doesn't need to be constrained to the window, so we will be consistent with the context menu. Even the current (non-refactored) dropdown is not constrained on the horizontal direction, so there's not really a point in forcing that constraint so much on desktop.

What happens instead?

The dropdown is constrained by the window boundaries.