Always define ExtWindows.activeWindow
Created by: lguychard
Fixes https://github.com/sourcegraph/sourcegraph/issues/8519
This changes ExtWindows to initialize activeWindow
in the constructor, and keep the same active window for its entire lifetime, rather than starting out with an undefined activeWindow
and adding/removing it as editors are added/removed.
This makes it possible for extension to call methods on sourcegraph.activeWindow
(such as showNotification()
and showInputBox()
) on all pages where the extension host is active, rather than solely on code view pages.