This CL also includes two related changes:
1. Support serialization of raw PSSH box;
2. Refactor segmenter interface a bit.
Change-Id: I668aa01a5a5ff524ad6fe74976339a3fd499120a
User should not need to care about how and when to call these APIs.
Internal code should call them automatically.
Change-Id: Ibc85a709d4e82ecc7b477986cabf09dcfc2e100c
The information is generated by Edwin's copyright.py script with some
minor manual modifications.
Chromium's original copyright notice is not replaced.
Also add LICENSE file taken from
https://sites.google.com/a/google.com/ospo/releasing#TOC-BSD-License
Change-Id: I231f09af96a0a611b1ca81e95cab82e12d7f529b