- Tracks other than video are protected using whole-block full-sample
encryption as specified in ISO/IEC 23001-7:2016(E) 9.7, which is
equivalent to a pattern of 1:0. This is different to the non pattern
encryption counterparts.
- Also updated the code to allow the existence of other protection
schemes in the original content, which will simply be ignored.
- The internal cryptor used by AesPatternCryptor should not use
constant iv, add a DCHECK for that.
- Optimize AesPatternCryptor handling on the special pattern 1:0.
Change-Id: Idc704e7bc6b347741336f38c6d3620fc19392960
Kongqun Yang