Backed out 3 changesets (bug 855971, bug 820846) because of browser-chrome test failures

Backed out changeset a2245b038bcc (bug 855971)
Backed out changeset 2a999f8ee317 (bug 820846)
Backed out changeset 6dba144500f3 (bug 820846)
Bug 868782 - Fix rooting hazards in txMozillaXSLTProcessor.cpp; r=till
Bug 868783 - Fix rooting hazards in nsXBLSerialize.cpp; r=till
Bug 868784 - Fix rooting hazards in nsCrypto.cpp; r=till