am 7755cdd6: Remove unused/debugging code from MP4 file writer

Merge commit '7755cdd69690ccbb42c6fd47b3e9c4594d4ade82' into gingerbread-plus-aosp

* commit '7755cdd69690ccbb42c6fd47b3e9c4594d4ade82':
  Remove unused/debugging code from MP4 file writer