[VCN14] Expose registerBestMatchingNetworkCallback

Test: m -j doc-comment-check-docs
Bug: 175662146
Change-Id: Ie67dd2f4f8d973de37bc64a03908d7cbb7c2b7ad

framework/src/android/net/ConnectivityManager.java

@@ -4241,9 +4241,27 @@ public class ConnectivityManager {
     }
 
     /**
-     * @hide
+     * Registers to receive notifications about the best matching network which satisfy the given
+     * {@link NetworkRequest}.  The callbacks will continue to be called until
+     * either the application exits or {@link #unregisterNetworkCallback(NetworkCallback)} is
+     * called.
+     *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * {@link #registerNetworkCallback} and its variants and {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
+     *
+     * @param request {@link NetworkRequest} describing this request.
+     * @param networkCallback The {@link NetworkCallback} that the system will call as suitable
+     *                        networks change state.
+     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
-    // TODO: Make it public api.
     @SuppressLint("ExecutorRegistration")
     public void registerBestMatchingNetworkCallback(@NonNull NetworkRequest request,
             @NonNull NetworkCallback networkCallback, @NonNull Handler handler) {