Some apps, like focusTimer <https://github.com/dmose/focusTimer>, want their windows to appear without any chrome (no titlebar, no menubar, no frame, etc.), so the desktop runtime should support that.

Should we support a new manifest property to allow that? Or do we want to provide an API to control the chrome interface?

For example we could extend the "chrome" property to let developers select what they want to enable (or disable) of the chrome UI.

For my particular app, I'd want to be able to at least drag the window around, so I really want to just disable most of the chrome (ie everything except the frame). My guess is that individual apps would have differing desires. Perhaps reusing some of the "features" argument stuff from window.open might be interesting here. I could imagine that might well be interesting to enable / disable this stuff dynamically, as well, which would seem to suggest some other (JavaScript?) interface than the manifest. The trick, of course, will be figuring out what stuff is worth the cost of supporting, and what interactions with the trust model there are.

I personally would remove the main menu completely. For the remove of the frame, we would need new JS APIs to maximize, minimize, close (also the main window, which has not been opened by window.open) and move the window. Besides, it would certainly be cool if you could use the "fullscreen" manifest field also in desktop apps (for games for example)...

Per bug 1238079, we're going to disable the desktop web runtime and remove it from the codebase, so we won't fix these bugs in it.