Add audio playback (all platforms) to cast_receiver_app.

media/cast/test/utility/in_process_receiver.cc

Index: media/cast/test/utility/in_process_receiver.cc
diff --git a/media/cast/test/utility/in_process_receiver.cc b/media/cast/test/utility/in_process_receiver.cc
index 9d78e084b3e75bb253752e68b706b4959dddefc8..ada4da4774eae7e2d3ec56f85a41ecf1ab2ab20f 100644
--- a/media/cast/test/utility/in_process_receiver.cc
+++ b/media/cast/test/utility/in_process_receiver.cc
@@ -66,13 +66,6 @@ void InProcessReceiver::StopOnMainThread(base::WaitableEvent* event) {
   event->Signal();
 }
 
-void InProcessReceiver::DestroySoon() {
-  cast_environment_->PostTask(
-      CastEnvironment::MAIN,
-      FROM_HERE,
-      base::Bind(&InProcessReceiver::WillDestroyReceiver, base::Owned(this)));
-}
-
 void InProcessReceiver::UpdateCastTransportStatus(CastTransportStatus status) {
   LOG_IF(ERROR, status == media::cast::transport::TRANSPORT_SOCKET_ERROR)
       << "Transport socket error occurred.  InProcessReceiver is likely dead.";
@@ -132,10 +125,5 @@ void InProcessReceiver::PullNextVideoFrame() {
       &InProcessReceiver::GotVideoFrame, weak_factory_.GetWeakPtr()));
 }
 
-// static
-void InProcessReceiver::WillDestroyReceiver(InProcessReceiver* receiver) {
-  DCHECK(receiver->cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
-}
-
 }  // namespace cast
 }  // namespace media