Android: Add common function for adding/releasing native reference

webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc

Index: webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
diff --git a/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc b/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
index 5172df2077de860c667f48f8969c83b3486e76ea..e594c1d3a9599596884b683928a11179ec2dbb35 100644
--- a/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
+++ b/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
@@ -57,10 +57,6 @@ static rtc::scoped_refptr<webrtc::PeerConnectionInterface> ExtractNativePC(
       reinterpret_cast<webrtc::PeerConnectionInterface*>(j_p));
 }
 
-JOW(void, PeerConnection_freePeerConnection)(JNIEnv*, jclass, jlong j_p) {
-  CHECK_RELEASE(reinterpret_cast<webrtc::PeerConnectionInterface*>(j_p));
-}
-
 JOW(void, PeerConnection_freeObserver)(JNIEnv*, jclass, jlong j_p) {
   PeerConnectionObserverJni* p =
       reinterpret_cast<PeerConnectionObserverJni*>(j_p);