[ Merge of http://go/wvgerrit/128143 ]
Now reports LICENSE_STATE_ERROR rather than ERROR_DRM_GENERIC_PLUGIN
to make the cause of failure and suggested action more clear for app
developers. Also added an additional error log.
Bug: 190645000
Test: WV unit/integration tests
Change-Id: Ib23ca628c590316f90f497d8fdfbab24fd644d6f