Fix google-explicit-constructor warnings in sensorservice.

* Add explicit keyword to conversion constructors,
  or use NOLINT for implicit converters.
Bug: 28341362
Test: build with WITH_TIDY=1

Change-Id: Ie7c4dfcdbd069809e103f0dd008ae2fb4b0502f4
diff --git a/services/sensorservice/SensorEventAckReceiver.h b/services/sensorservice/SensorEventAckReceiver.h
index 998597a..20fa4c7 100644
--- a/services/sensorservice/SensorEventAckReceiver.h
+++ b/services/sensorservice/SensorEventAckReceiver.h
@@ -27,7 +27,7 @@
     sp<SensorService> const mService;
 public:
     virtual bool threadLoop();
-    SensorEventAckReceiver(const sp<SensorService>& service)
+    explicit SensorEventAckReceiver(const sp<SensorService>& service)
             : mService(service) {
     }
 };