Sync changes with mozilla-central copy.  Includes BMO 1062293, 1057199,
848954, 1054176, 1052923, 1046592, 1049478, 1046470, 1045018, 1023947,
1027713, 1015932, 1032266, 1034140, 1033192, 1020227, 1017438, 1026854,
1008079, 1007552.
jack: trivial compile fix (untested)