In bug 1556556, we added a new FrameForPointOption for nsLayoutUtils::GetFrameForPoint(), named IsRelativeToLayoutViewport.

Later in the patch series we introduce a RelativeTo structure which groups a frame with a viewport type that can be either layout or visual.

We can clean this up a bit by having GetFrameForPoint take a RelativeTo parameter, and replacing the IsRelativeToLayoutViewport flag with the use of ViewportType::Layout in that parameter.

Going through the call sites of this function has also turned up call sites that were passing in the incorrect viewport type, so this change may fix some correctness issues as well.

This allows headers which nsLayoutUtils.h includes to use these types without
creating a circular dependency.

As part of this change, the types are also moved into namespace mozilla.

This removes the need for FrameForPointOptions::IsRelativeToLayoutViewport,
and makes sure each call site of these functions indicates whether the
input point/rect is in visual or layout coordinates.

Several call sites were passing in layout coordinates without setting the
IsRelativeToLayoutViewport flag, which this patch corrects.

Depends on D71704

For posterity this was backed out along with bug 1556556, see this comment.

https://hg.mozilla.org/mozilla-central/rev/b0a06e58b247
https://hg.mozilla.org/mozilla-central/rev/cd5ab4e2f7a8