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 35b742bc9e8f42f1d15b7d638e0c19b7aee2d54a..dab518244b93c83a4964d4270fde4df9d89382bf 100644
--- a/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
+++ b/webrtc/sdk/android/src/jni/pc/peerconnection_jni.cc
@@ -57,14 +57,6 @@ static rtc::scoped_refptr<webrtc::PeerConnectionInterface> ExtractNativePC(
       reinterpret_cast<webrtc::PeerConnectionInterface*>(j_p));
 }
 
-JNI_FUNCTION_DECLARATION(void,
-                         PeerConnection_freePeerConnection,
-                         JNIEnv*,
-                         jclass,
-                         jlong j_p) {
-  reinterpret_cast<webrtc::PeerConnectionInterface*>(j_p)->Release();
-}
-
 JNI_FUNCTION_DECLARATION(void,
                          PeerConnection_freeObserver,
                          JNIEnv*,