Don't bootloop if GNSS is unavailable.

Bug: 231740141
Test: build and flash a "car" device without GNSS
Change-Id: I0891812f6c83fb1f000d5aeccf5f6b9d2e197dc3

services/core/java/com/android/server/timedetector/GnssTimeUpdateService.java

@@ -116,6 +116,11 @@ public final class GnssTimeUpdateService extends Binder {
             Log.d(TAG, "requestGnssTimeUpdates()");
         }
 
+        if (!mLocationManager.hasProvider(LocationManager.GPS_PROVIDER)) {
+            Log.e(TAG, "GPS provider does not exist on this device");
+            return;
+        }
+
         // Location Listener triggers onLocationChanged() when GNSS data is available, so
         // that the getGnssTimeMillis() function doesn't need to be continuously polled.
         mLocationListener = new LocationListener() {

services/tests/servicestests/src/com/android/server/timedetector/GnssTimeUpdateServiceTest.java

@@ -85,6 +85,9 @@ public final class GnssTimeUpdateServiceTest {
         when(mMockContext.getSystemService(AlarmManager.class))
                 .thenReturn(mMockAlarmManager);
 
+        when(mMockLocationManager.hasProvider(LocationManager.GPS_PROVIDER))
+                .thenReturn(true);
+
         LocalServices.addService(LocationManagerInternal.class, mLocationManagerInternal);
 
         mGnssTimeUpdateService =