startup writers: Release unique_ptr/lock correctly in ReturnTraceWriter am: 65080795f5 am: bdfcd82b9f
startup writers: Release unique_ptr/lock correctly in ReturnTraceWriter am: 65080795f5 am: bdfcd82b9f

Change-Id: Ifdaa584ddcd20331824c656072097cf0f864235f

google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto