Fix decoder instantiation during playback

When a decoder is created while another decoder
is in use and the two decoders share a common
crypto instance, decryption results would become
indeterminate, which could cause the decoder to
hang. This change adds a notification to the
crypto instance so it can update state when its
ownership changes.

bug: 36209723

Test: playbacktests-debug-androidTest.apk as
described in the bug.

Change-Id: I453c260eace5543dd79a3569bf6a9592394c4113