Fixing bug 781310. Change nsPluginHost::GetInst() to return already_AddRefed<nsPluginHost> to make it harder to write leaky code. r=jschoenick@mozilla.com
Bug 822086 - Handle a nullptr ContainerLayer in nsDisplayTransform::BuildLayer. r=bustage CLOSED TREE
Backout bug 852831 (07e459058893) on a CLOSED TREE.