[ 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