[ Merge of http://go/wvgerrit/138089 ]
Non-hidl code is no longer needed in the widevine android plugin. By
doing work this cleanup will save the team from having to keep
maintaining code that isn't needed anymore.
Clean up steps taken as follows:
1. Remove non-hidl code but keep commonly used code
2. Remove legacy test code
3. Remove legacy test build and test entry
Bug: 69573078
Bug: 172285246
Test: unit tests, GtsMediaTestCases, CtsMediaDrmTestCases
Change-Id: I75938d69413c631ef6be82da3d885ba173efc581
0b02296014