am 4d8ceada: am dbfd055d: am a6f1104b: Use pread() to get the decrypted data for container based DRM file. For bug 4392094.

* commit '4d8ceada09441f43a98f5c7dadde9192e7d6abf9':
  Use pread() to get the decrypted data for container based DRM file. For bug 4392094.