Bug 1009980 - Fix the SurfaceSteam readback for Canvas 2D screenshot. r=snorp, a=1.4+
Bug 1006957 - Handle buffer ownership between SurfaceStream and CanvasClient. r=nical, a=1.4+
Bug 1015331 - Do not leak Task object created during fling handoff. r=kats, a=1.4+
Bug 1015006 - Detect USB cable unplugged and set sharing to false. r=qDot, a=1.4+

If the USB cable is pulled after we call SetIsSharing(true) but before we actually initiate the
sharing operation, then the volume doesn't change state, and mIsSharing never gets set back to
false. So we detect this condition now and force mIsSharing to be false when the USB cable is
unplugged.