[ Merge of http://go/wvgerrit/84607 ]
[ Merge of http://go/wvgerrit/84608 ]
The primary goal is to replace the use of `rand()` with the random
number generators provided with the C++11 standard.
This simplified generator wraps some of the technical aspects of the
<random> library and provides an interface for uniformly distributed
integers.
As part of the `rand()` purge in the CDM, all uses of the C random int
function in `core()` have been removed. Places that previously used
`rand()` now use `CdmRandom` facilities.
Test: Linux unittest and Android unittest
Bug: 130680365
Change-Id: Ica383870536ed462dbb80e630c2d66845e38b937
ee56d93454