Add NDK support for new head tracker sensor type

Bug: 210156629
Test: presubmit (definitions only)
Change-Id: Ie93f3a99a3215690ab585b2e248edf096712c8c0
diff --git a/libs/sensor/Sensor.cpp b/libs/sensor/Sensor.cpp
index 0a49008..e1560c0 100644
--- a/libs/sensor/Sensor.cpp
+++ b/libs/sensor/Sensor.cpp
@@ -276,6 +276,10 @@
         mStringType = SENSOR_STRING_TYPE_HINGE_ANGLE;
         mFlags |= SENSOR_FLAG_ON_CHANGE_MODE;
         break;
+    case SENSOR_TYPE_HEAD_TRACKER:
+        mStringType = SENSOR_STRING_TYPE_HEAD_TRACKER;
+        mFlags |= SENSOR_FLAG_CONTINUOUS_MODE;
+        break;
     default:
         // Only pipe the stringType, requiredPermission and flags for custom sensors.
         if (halVersion > SENSORS_DEVICE_API_VERSION_1_0 && hwSensor.stringType) {