other browser rotate their screen based on phone's orientation. we should do this.
I think it would be great to have the ability to do this, but I'm not sure we would want to always do it. Probably needs more user testing.
I think we need this for winmo, especially on high dpi WVGA screens. There can be a primary UI pref for users to disable it.
I think we fixed this in bug https://bugzilla.mozilla.org/show_bug.cgi?id=541015
Verified fix based on bug 541015