MacViews: Bubbles and dialogs behave more like sheets wrt main status

Currently dialog boxes do not take main status from the parent window.
Change this so that any child window does not become a main window.

Also, use the same trick that Cocoa bubbles use to avoid the traffic
lights dimming, but only do this for child windows that don't have their
own traffic lights.


Review URL:

Cr-Commit-Position: refs/heads/master@{#372036}
4 files changed