Added support for changing the volume of AudioTrack as discussed in BUG=webrtc:6533

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

Index: webrtc/sdk/android/src/jni/peerconnection_jni.cc
diff --git a/webrtc/sdk/android/src/jni/peerconnection_jni.cc b/webrtc/sdk/android/src/jni/peerconnection_jni.cc
index 75b1bad20256dcafd288b6a953d8e686c8a216ca..bff82e1f60f2fdb9a2a42b6f18703c6e4522654f 100644
--- a/webrtc/sdk/android/src/jni/peerconnection_jni.cc
+++ b/webrtc/sdk/android/src/jni/peerconnection_jni.cc
@@ -1199,6 +1199,16 @@ JOW(void, PeerConnectionFactory_shutdownInternalTracer)(JNIEnv* jni, jclass) {
   rtc::tracing::ShutdownInternalTracer();
 }
 
+JOW(void, AudioTrack_nativeSetVolume)
+(JNIEnv*, jclass, jlong j_p, jdouble volume) {
+  rtc::scoped_refptr<AudioSourceInterface> source(
+      reinterpret_cast<AudioTrackInterface*>(j_p)->GetSource());
+
+  jlong nativePointer = jlongFromPointer(source.get());

[magjed_webrtc, 2017/04/05 19:14:00]

It looks like you are converting AudioSourceInterface to jlong and then back to
AudioSourceInterface again. Can't you just replace the last two lines with:
source->SetVolume(volume);
?

+
+  reinterpret_cast<AudioSourceInterface*>(nativePointer)->SetVolume(volume);
+}
+
 // Helper struct for working around the fact that CreatePeerConnectionFactory()
 // comes in two flavors: either entirely automagical (constructing its own
 // threads and deleting them on teardown, but no external codec factory support)