Backed out 8 changesets (bug 1679440, bug 1682069, bug 1667276) for causing...

Backed out 8 changesets (bug 1679440, bug 1682069, bug 1667276) for causing failure on test_crash_backgroundtask_moz_crash.js. CLOSED TREE

Backed out changeset f06504e3219f (bug 1682069)
Backed out changeset 4d325f68ea24 (bug 1679440)
Backed out changeset 9ab334e527a5 (bug 1667276)
Backed out changeset 1c8d51d2c90f (bug 1667276)
Backed out changeset 8d6f10d83c6b (bug 1667276)
Backed out changeset 62488ec634f9 (bug 1667276)
Backed out changeset 1dcb2d1be264 (bug 1667276)
Backed out changeset c673fff5bd85 (bug 1667276)