Merge from Widevine repo of http://go/wvgerrit/169064
This CL should cleanup some minor issues that existed after the initial
CLs refactoring the unit tests went in. The issues fixed should be:
1) duplicate decrypt tests
2) decrypt tests added to be run
3) removed unecessary header files
4) refactored some provisioning tests that I had previously overlooked
Bug: 253779846
Merged from https://widevine-internal-review.googlesource.com/167537
Change-Id: Ic474fbcf69a08c0482b5e74d0c80be2cd16702d8
