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 a9fe97d8c2f8c16137c70db4f0084ce0f1d18e9f..dd13f736c34049c00b02a0d18458a30a211f3658 100644
--- a/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
+++ b/webrtc/sdk/android/src/jni/pc/rtpsender_jni.cc
@@ -83,13 +83,4 @@ JNI_FUNCTION_DECLARATION(jstring,
                ->id());
 }
 
-JNI_FUNCTION_DECLARATION(void,
-                         RtpSender_free,
-                         JNIEnv* jni,
-                         jclass,
-                         jlong j_rtp_sender_pointer) {
-  reinterpret_cast<webrtc::RtpSenderInterface*>(j_rtp_sender_pointer)
-      ->Release();
-}
-
 }  // namespace webrtc_jni