Add android bindings for PeerConnectionState.

This change makes it possible for android apps to use the new standards-compliant PeerConnectionState.

Bug: webrtc:9977
Change-Id: Iad19c38e664a59e86879715ec7a04a59a9894bee
Reviewed-on: https://webrtc-review.googlesource.com/c/109883
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Jonas Olsson <jonasolsson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25652}

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

@@ -50,6 +50,21 @@ public class PeerConnection {
     }
   }
 
+  /** Tracks PeerConnectionInterface::PeerConnectionState */
+  public enum PeerConnectionState {
+    NEW,
+    CONNECTING,
+    CONNECTED,
+    DISCONNECTED,
+    FAILED,
+    CLOSED;
+
+    @CalledByNative("PeerConnectionState")
+    static PeerConnectionState fromNativeIndex(int nativeIndex) {
+      return values()[nativeIndex];
+    }
+  }
+
   /** Tracks PeerConnectionInterface::TlsCertPolicy */
   public enum TlsCertPolicy {
     TLS_CERT_POLICY_SECURE,
@@ -79,6 +94,10 @@ public class PeerConnection {
     /** Triggered when the IceConnectionState changes. */
     @CalledByNative("Observer") void onIceConnectionChange(IceConnectionState newState);
 
+    /** Triggered when the PeerConnectionState changes. */
+    @CalledByNative("Observer")
+    default void onConnectionChange(PeerConnectionState newState) {}
+
     /** Triggered when the ICE connection receiving status changes. */
     @CalledByNative("Observer") void onIceConnectionReceivingChange(boolean receiving);
 
@@ -1093,6 +1112,10 @@ public class PeerConnection {
     return nativeIceConnectionState();
   }
 
+  public PeerConnectionState connectionState() {
+    return nativeConnectionState();
+  }
+
   public IceGatheringState iceGatheringState() {
     return nativeIceGatheringState();
   }
@@ -1167,6 +1190,7 @@ public class PeerConnection {
   private native boolean nativeSetBitrate(Integer min, Integer current, Integer max);
   private native SignalingState nativeSignalingState();
   private native IceConnectionState nativeIceConnectionState();
+  private native PeerConnectionState nativeConnectionState();
   private native IceGatheringState nativeIceGatheringState();
   private native void nativeClose();
   private static native long nativeCreatePeerConnectionObserver(Observer observer);