Fix dangerous unsafe_get() in SensorRecord

Change raw pointers to wp<> and constify relevant lines in
SensorRecord.

Bug: 30261110

Change-Id: I7f28c593366af44192991061fa5f71cf925b22a8
(cherry picked from commit ded526e8c3539b5986b46dffc1ff8ab15d7da570)
diff --git a/services/sensorservice/SensorEventConnection.h b/services/sensorservice/SensorEventConnection.h
index b796cc0..883c16e 100644
--- a/services/sensorservice/SensorEventConnection.h
+++ b/services/sensorservice/SensorEventConnection.h
@@ -52,7 +52,7 @@
                           bool isDataInjectionMode, const String16& opPackageName);
 
     status_t sendEvents(sensors_event_t const* buffer, size_t count, sensors_event_t* scratch,
-                        SensorEventConnection const * const * mapFlushEventsToConnections = NULL);
+                        wp<const SensorEventConnection> const * mapFlushEventsToConnections = NULL);
     bool hasSensor(int32_t handle) const;
     bool hasAnySensor() const;
     bool hasOneShotSensors() const;