DOM.layoutBounds

The bounds of the Layout viewport, as discussed in
A tale of two viewports — part two;
but honoring the constraints as specified applicable viewport meta-tag.

The bounds returned are not guaranteed to be fully aligned with CSS media queries (see
What size is my viewport?).

This is not representative of the Visual bounds: in particular the non-primary axis will
generally be significantly larger than the screen height on mobile devices when running with a
constrained viewport.

The properties change dynamically.