Make sure to delete jni_id_manager_ on shutdown.

We were leaking the jni_id_manager_ on shutdown. Make the field a
unique_ptr to fix this issue.

Test: ./test.py --host
Bug: 136111027
Bug: 134162467
Change-Id: I2a65753d136195a2e2ff47d9a8eb6c37ec3918f6
2 files changed