After bug 573733, this is the second part to sync us with Firefox' bug 554005, it makes sense to move over to .tabContainer and instead deprecate .mTabContainer.
Created attachment 456632 [details] [diff] [review]
do the switch
This is easy, esp. as we already support both names, this patch moves the old one to be deprecated in accordance with Firefox.
Pushed as http://hg.mozilla.org/comm-central/rev/9bbc9b44bbf0