Bug 938071 - Fix typo in TabState.onSwapDocShells() r=billm

From efc26aa604f2770e3255bab13312a8e77dcea484 Mon Sep 17 00:00:00 2001
Bug 938084 - Drop pending collections when docShells are swapped r=billm

From c9f166092e28ede16159c7e067df5b307a68f145 Mon Sep 17 00:00:00 2001
Bug 938093 - Swap TabStateCache contents when docShells are swapped r=billm

From ca18aa2560b9380aa67ccfb6b90f4bbe8d38fc57 Mon Sep 17 00:00:00 2001