[cast/test] Use AudioConverter in FakeMediaSource to play back 6-channel WEBM's.

media/cast/test/simulator.cc

Index: media/cast/test/simulator.cc
diff --git a/media/cast/test/simulator.cc b/media/cast/test/simulator.cc
index 1e01085dddc6526e7ec37ef8165425271433689c..a4fa5a1ed3b6f7a51e8cb3918ca917e4e4ce47ed 100644
--- a/media/cast/test/simulator.cc
+++ b/media/cast/test/simulator.cc
@@ -480,6 +480,7 @@ void RunSimulation(const base::FilePath& source_path,
   const bool quality_test = !metrics_output_path.empty();
   FakeMediaSource media_source(task_runner,
                                &testing_clock,
+                               audio_sender_config,
                                video_sender_config,
                                quality_test);
   scoped_ptr<EncodedVideoFrameTracker> video_frame_tracker;