Hide start and cancel handover from api surface

* Since AOSP is in control of when IWlan allocates and releases the
  pdu session id, it doesn't need to react to start handover and
  cancel handover.
* CellularDataService can still use these methods since it is in
  AOSP.

Bug: 177607048
Test: make
Change-Id: I9e65ad178a843e92a59e5e4f7debd4d7b77a3edb

core/api/system-current.txt

@@ -11650,7 +11650,6 @@ package android.telephony.data {
 
   public abstract class DataService.DataServiceProvider implements java.lang.AutoCloseable {
     ctor public DataService.DataServiceProvider(int);
-    method public void cancelHandover(int, @NonNull android.telephony.data.DataServiceCallback);
     method public abstract void close();
     method public void deactivateDataCall(int, int, @Nullable android.telephony.data.DataServiceCallback);
     method public final int getSlotIndex();
@@ -11661,15 +11660,12 @@ package android.telephony.data {
     method public void setInitialAttachApn(@NonNull android.telephony.data.DataProfile, boolean, @NonNull android.telephony.data.DataServiceCallback);
     method public void setupDataCall(int, @NonNull android.telephony.data.DataProfile, boolean, boolean, int, @Nullable android.net.LinkProperties, @NonNull android.telephony.data.DataServiceCallback);
     method public void setupDataCall(int, @NonNull android.telephony.data.DataProfile, boolean, boolean, int, @Nullable android.net.LinkProperties, @IntRange(from=0, to=15) int, @Nullable android.telephony.data.SliceInfo, @NonNull android.telephony.data.DataServiceCallback);
-    method public void startHandover(int, @NonNull android.telephony.data.DataServiceCallback);
   }
 
   public class DataServiceCallback {
     method public void onApnUnthrottled(@NonNull String);
     method public void onDataCallListChanged(@NonNull java.util.List<android.telephony.data.DataCallResponse>);
     method public void onDeactivateDataCallComplete(int);
-    method public void onHandoverCancelled(int);
-    method public void onHandoverStarted(int);
     method public void onRequestDataCallListComplete(int, @NonNull java.util.List<android.telephony.data.DataCallResponse>);
     method public void onSetDataProfileComplete(int);
     method public void onSetInitialAttachApnComplete(int);

telephony/java/android/telephony/data/DataService.java

@@ -283,6 +283,8 @@ public abstract class DataService extends Service {
          *
          * @param cid The identifier of the data call which is provided in {@link DataCallResponse}
          * @param callback The result callback for this request.
+         *
+         * @hide
          */
         public void startHandover(int cid, @NonNull DataServiceCallback callback) {
             // The default implementation is to return unsupported.
@@ -303,6 +305,8 @@ public abstract class DataService extends Service {
          *
          * @param cid The identifier of the data call which is provided in {@link DataCallResponse}
          * @param callback The result callback for this request.
+         *
+         * @hide
          */
         public void cancelHandover(int cid, @NonNull DataServiceCallback callback) {
             // The default implementation is to return unsupported.

telephony/java/android/telephony/data/DataServiceCallback.java

@@ -191,6 +191,8 @@ public class DataServiceCallback {
      * Called to indicate result for the request {@link DataService#startHandover}.
      *
      * @param result The result code. Must be one of the {@link ResultCode}
+     *
+     * @hide
      */
     public void onHandoverStarted(@ResultCode int result) {
         if (mCallback != null) {
@@ -209,6 +211,8 @@ public class DataServiceCallback {
      * Called to indicate result for the request {@link DataService#cancelHandover}.
      *
      * @param result The result code. Must be one of the {@link ResultCode}
+     *
+     * @hide
      */
     public void onHandoverCancelled(@ResultCode int result) {
         if (mCallback != null) {