Backed out 6 changesets (bug 974745, bug 975210, bug 974736, bug 972936, bug 972930, bug 975228) for browser_tabopen_reflows.js bustage
CLOSED TREE

Backed out changeset 5aed75c602ce (bug 974745)
Backed out changeset 208ba43a7098 (bug 975210)
Backed out changeset 5227bbca70f0 (bug 974736)
Backed out changeset a695139e96ee (bug 972936)
Backed out changeset 8524260ce49a (bug 972930)
Backed out changeset 667fc810ab49 (bug 975228)