Merge changes Id23d3d54,I7ba05b48,I69c962da into gce-dev

* changes:
  Uses new Packet struct instead of Message for shm
  Adds Packet struct
  Adds constant for max message size
tree: a9586eadeba83849eea9a465a4def928b6847b63
  1. common/
  2. guest/
  3. host/
  4. tools/
  5. Android.bp
  6. Android.mk
  7. OWNERS