Bug 952062.  Fix union codegen to properly destroy the union members if conversion to them fails.  r=dzbarsky
Bug 887538 - Implement web components shadow element. r=mrbkap
No bug, Automated HSTS preload list update from host bld-centos6-hp-016 - a=hsts-update
No bug, Automated blocklist update from host bld-linux64-ix-037 - a=blocklist-update
merge mozilla-inbound to mozilla-central
merge fx-team to mozilla-central