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/SensorService.cpp b/services/sensorservice/SensorService.cpp
index a24740b..dbd0624 100644
--- a/services/sensorservice/SensorService.cpp
+++ b/services/sensorservice/SensorService.cpp
@@ -260,7 +260,7 @@
             const size_t minBufferSize = SensorEventQueue::MAX_RECEIVE_BUFFER_EVENT_COUNT;
             mSensorEventBuffer = new sensors_event_t[minBufferSize];
             mSensorEventScratch = new sensors_event_t[minBufferSize];
-            mMapFlushEventsToConnections = new SensorEventConnection const * [minBufferSize];
+            mMapFlushEventsToConnections = new wp<const SensorEventConnection> [minBufferSize];
             mCurrentOperatingMode = NORMAL;
 
             mNextSensorRegIndex = 0;