Backed out 7 changesets (bug 1888756) for potentially causing Session History crashes. a=backout
Backed out changeset 85022f2e4129 (bug 1888756)
Backed out changeset 1458ad53d229 (bug 1888756)
Backed out changeset a84d886d8753 (bug 1888756)
Backed out changeset efff3e5e95c2 (bug 1888756)
Backed out changeset 400a8ff57ae4 (bug 1888756)
Backed out changeset 04180e2fb99d (bug 1888756)
Backed out changeset 0eb8b13b0717 (bug 1888756)
gecko-commit: deea4a904a0d3d546ab359aeca91a4bb6dc02a77
gecko-reviewers: backout