Android: Add common function for adding/releasing native reference

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

Index: webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
diff --git a/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc b/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
index 36aad593cddf0b47b4e068dab66ecca6c1f14772..b2984c26da7c9f2ec0c31ee5be712f6ea54ed117 100644
--- a/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
+++ b/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
@@ -63,9 +63,4 @@ JOW(jstring, RtpSender_nativeId)
                ->id());
 }
 
-JOW(void, RtpSender_free)(JNIEnv* jni, jclass, jlong j_rtp_sender_pointer) {
-  reinterpret_cast<webrtc::RtpSenderInterface*>(j_rtp_sender_pointer)
-      ->Release();
-}
-
 }  // namespace webrtc_jni