Monitor binder status to media.metrics service

Add code to use binder's linkToDeath() so that our clients learn when
(infrequently, we hope) the media.metrics service dies for some
reason. When this happens, arrange for the client to re-establish
its connection to the service.

Bug: 66948389
Test: kill media.metrics, watch logcat for reestablishment messages
Change-Id: Ic518b955ce6816698b21e6a9c844587cef2e2712