Add the new Stagefright ANativeWindow OMX codec API.

This change defines the two OMX_SetParameter calls that enable OMX codecs to
interact with ANativeWindows.  It also adds the plumbing to the IOMX, OMX, and
OMXNodeInstance classes to use these new APIs.

Change-Id: Ibfbf893dc3513db0b3d3221bec5708c77287cddc