b331822558
(This contains a merge of http://go/wvgerrit/13382 from the Widevine repository.) This undoes the previous change to silence harmless C++11 narrowing warnings and instead changes the code to no longer trigger them. The fix was to delcare the type of our PSSH prefix constant to be uint8_t* and then convert it to char* at usage-time rather than defining the not-technically-char* data as a char* to start. Change-Id: I68ff8c3ed0859096863b49c61cd60ae8461b5b29