Expose peer connection's getStats by RtpSender/Receiver in Android SDK

Currently if you want to obtain the stats for a specific sender/receiver
in Android, you need to call peerConnection.getStats() and filter
manually the result by sender.

pc.getStats(receiver/sender) exists in c++ and ios but was not exposed
in Android

Bug: webrtc:14547
Change-Id: I9954434880f0f93821fcd2e2de24a875e8d136ae
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/275880
Reviewed-by: Xavier Lepaul‎ <xalep@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38428}

sdk/android/api/org/webrtc/PeerConnection.java

@@ -1176,6 +1176,22 @@ public class PeerConnection {
     nativeNewGetStats(callback);
   }
 
+  /**
+   * Gets stats using the new stats collection API, see webrtc/api/stats/. These
+   * will replace old stats collection API when the new API has matured enough.
+   */
+  public void getStats(RtpSender sender, RTCStatsCollectorCallback callback) {
+    nativeNewGetStatsSender(sender.getNativeRtpSender(), callback);
+  }
+
+  /**
+   * Gets stats using the new stats collection API, see webrtc/api/stats/. These
+   * will replace old stats collection API when the new API has matured enough.
+   */
+  public void getStats(RtpReceiver receiver, RTCStatsCollectorCallback callback) {
+    nativeNewGetStatsReceiver(receiver.getNativeRtpReceiver(), callback);
+  }
+
   /**
    * Limits the bandwidth allocated for all RTP streams sent by this
    * PeerConnection. Pass null to leave a value unchanged.
@@ -1310,6 +1326,8 @@ public class PeerConnection {
   private native void nativeRemoveLocalStream(long stream);
   private native boolean nativeOldGetStats(StatsObserver observer, long nativeTrack);
   private native void nativeNewGetStats(RTCStatsCollectorCallback callback);
+  private native void nativeNewGetStatsSender(long sender, RTCStatsCollectorCallback callback);
+  private native void nativeNewGetStatsReceiver(long receiver, RTCStatsCollectorCallback callback);
   private native RtpSender nativeCreateSender(String kind, String stream_id);
   private native List<RtpSender> nativeGetSenders();
   private native List<RtpReceiver> nativeGetReceivers();

sdk/android/api/org/webrtc/RtpReceiver.java

@@ -49,6 +49,12 @@ public class RtpReceiver {
     return nativeGetId(nativeRtpReceiver);
   }
 
+  /** Returns a pointer to webrtc::RtpReceiverInterface. */
+  long getNativeRtpReceiver() {
+    checkRtpReceiverExists();
+    return nativeRtpReceiver;
+  }
+
   @CalledByNative
   public void dispose() {
     checkRtpReceiverExists();