Mark adhoc conference call APIs as @hide.

Test: make -j update-api
Test: Run unit tests
Bug: 62151032
Change-Id: I8fe9c4d2c9a8861deea3a0def82c432762cd1222
diff --git a/telecomm/java/android/telecom/Connection.java b/telecomm/java/android/telecom/Connection.java
index f974be5..48ed6ae 100644
--- a/telecomm/java/android/telecom/Connection.java
+++ b/telecomm/java/android/telecom/Connection.java
@@ -378,7 +378,8 @@
 
     /**
      * When set, indicates that this {@link Connection} supports initiation of a conference call
-     * by directly adding a participant using {@link #onAddConferenceParticipants()}.
+     * by directly adding participants using {@link #onAddConferenceParticipants(List)}.
+     * @hide
      */
     public static final int CAPABILITY_ADD_PARTICIPANT = 0x04000000;
     //**********************************************************************************************
@@ -2960,9 +2961,10 @@
     public void onSeparate() {}
 
     /**
-     * Supports initiation of a conference call by directly adding participants.
+     * Supports initiation of a conference call by directly adding participants to an ongoing call.
      *
      * @param participants with which conference call will be formed.
+     * @hide
      */
     public void onAddConferenceParticipants(@NonNull List<Uri> participants) {}