GitLab

- Implement StreamInformation for video size notification.
- Implement the XAVolumeItf for volume control
- Fix bug in GUID -> MPH hash.
- Fixed typo in GenericPlayer::pause() log
- Do not signal a discontinuity automatically when the ABQ is
  cleared because clearing the queue doesn't imply there will
  be a discontinuity in the data (e.g. the same data that was
  cleared could be reenqueued)
- In "native-media" test app: add test code to exercise the
  XAVolumeItf functionality.

Change-Id: I9f69f8cacbdce51b6d96d60141ec1d0f645df991