Merge from widevine repo of http://go/wvgerrit/21260
This CL adds some oemcrypto unit tests for various buffer sizes, as
described in b/28887904 and the OEMCrypto v12 specification.
Encryption and Decryption buffers can be 100k large. License request
and response messages can be 8k. A provider session token (pst) can be
at most 255 bytes long.
I also passed the code through clang-format.
b/28887904
Change-Id: Ia3e317c0f6466e663461e66b610c9a98a90efb0a
67b06a70e4