Minor fixes to RegistrationIntentService

Author: Alex Ames

messaging/src/android/java/com/google/firebase/messaging/cpp/RegistrationIntentService.java

@@ -16,6 +16,7 @@
 
 import android.content.Context;
 import android.content.Intent;
+import androidx.core.app.JobIntentService;
 import com.google.firebase.iid.FirebaseInstanceId;
 import com.google.flatbuffers.FlatBufferBuilder;
 import java.io.FileOutputStream;
@@ -36,15 +37,6 @@ public RegistrationIntentService() {
     super(TAG);
   }
 
-  /**
-   * Convenience wrapper over enqueueWork to either directly start the service (when running on
-   * pre-O platforms) or enqueue work for it as a job (when running on Android O and later).
-   */
-  public static void enqueueWork(Context context, Intent intent) {
-    enqueueWork(
-        context, RegistrationIntentService.class, JobIds.REGISTRATION_INTENT_SERVICE, intent);
-  }
-
   // Fetch the latest registration token and notify the C++ layer.
   @Override
   protected void onHandleWork(@NonNull Intent intent) {