Bug 972622 - MakeCurrent during WebGL.compressedTex(Sub)Image2D(). r=kamidphish, a=lsblakk
Bug 941701 - Fix crash in TextTrackCue::GetCueAsHTML. r=rillian, a=lsblakk

TextTrackCue::GetCueAsHTML gets called when the HTMLMediaElement
shutsdown which means that TextTrackCue's mDocument sometimes no longer
exists based on when the cycle collector freed it. I've added a null
check to make sure that it exists before we start doing anything.
Bug 972097 - Fix merge failure (lost 'rtcp_'). r=padenot, a=lsblakk