Bug 820022 - Add null check for layerView. r=margaret
Bug 856877 - Initialize JSRuntime::interrupt.  r=wmccloskey.

--HG--
extra : rebase_source : 793f3357ea5850ecc282c7c150a8bdf71b5b78f9
Bug 742537 - Remove HTMLMediaElement.initialTime attribute. r=cpearce,doublec