[Mainline] Add @hide. Revisit and redesign in S

Bug: 144486008
Test: build pass.
Change-Id: I9f301b65a3a476a114821c77916dbdb988e5d983
diff --git a/api/system-current.txt b/api/system-current.txt
index e8e7fff..34e301c 100755
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -11331,7 +11331,6 @@
   public class ServiceState implements android.os.Parcelable {
     method public void fillInNotifierBundle(@NonNull android.os.Bundle);
     method public int getDataNetworkType();
-    method public int getDataRegistrationState();
     method @Nullable public android.telephony.NetworkRegistrationInfo getNetworkRegistrationInfo(int, int);
     method @NonNull public java.util.List<android.telephony.NetworkRegistrationInfo> getNetworkRegistrationInfoListForDomain(int);
     method @NonNull public java.util.List<android.telephony.NetworkRegistrationInfo> getNetworkRegistrationInfoListForTransportType(int);
diff --git a/telephony/java/android/telephony/ServiceState.java b/telephony/java/android/telephony/ServiceState.java
index 45cba51..dd20d06 100644
--- a/telephony/java/android/telephony/ServiceState.java
+++ b/telephony/java/android/telephony/ServiceState.java
@@ -580,7 +580,6 @@
      *
      * @hide
      */
-    @SystemApi
     public @RegState int getDataRegistrationState() {
         return getDataRegState();
     }