Bug 819070 - Don't restore session if Gecko is already running. r=mfinkle

--HG--
extra : rebase_source : 35f720d9815d6e54d09419002dd30e5ab87f2d1a
Bug 819398 - Build mobile with per-window private browsing support; r=mfinkle

--HG--
extra : rebase_source : 594a4f2a922b3ce4690709eca94e967bb4df674b
Bug 735399- Only do session restore after a crash. r=mfinkle
Bug 783490: Enable "layout.css.flexbox.enabled" pref. r=dbaron
Test only change / possible fix for Bug 759639 - Intermittent test_0202_app_launch_apply_update_dirlocked_svc.js | test failed (with xpcshell return code: 0), | pending-service == pending, | exception thrown from do_timeout callback: 2147500036. r=bbondy
Bug 817670 - Update Jetpack tests to pick up fixes to test failures. r=kwierso
back out 75cab729c971 because it landed with the wrong bug number
Bug 783409: Enable "layout.css.flexbox.enabled" pref. r=dbaron
Bug 819103 - Twitter fails to install from Marketplace [r=sicking]
Bug 818583 - Permissions Installer Tests. r=orange
Bug 819093 - Use strings for env values in remote mochitest; r=jmaher DONTBUILD
Bug 811755 - Add test for PreContentIterator in nsContentEventHandler; r=masayuki
Bug 818824 - Fire an event when no audio channel is playing now. r=baku, a=blocking-basecamp
Bug 787134 - Make links not in a document or with an invalid href respond to :link selector.  r=bzbarsky
Bug 819418 - part 0 - Histogram::SampleSet:Add needs to transfer all values, not just sum_; r=vdjeric
Bug 787134 - Fix apparent typo. r=me
Bug 819229 - Rename gatherStartupInformation to gatherStartupHistograms. r=vladan.
Turn PGO off for various functions (bug 791214, r=jandem).
Bug 819539 - Ignore _Unwind_Backtrace errors on ARM + Android. r=glandium
Bug 819526 - [SMS] Don't update the primary key in mostRecentStore  r=bent