[Chromecast] Process streams with different post-processing.

chromecast/public/media/media_pipeline_device_params.h

Index: chromecast/public/media/media_pipeline_device_params.h
diff --git a/chromecast/public/media/media_pipeline_device_params.h b/chromecast/public/media/media_pipeline_device_params.h
index 680da27cd25f9761209090867bb07ad37d56b041..4e1a64d9737a5a19183236fefa71cc1a45ee077d 100644
--- a/chromecast/public/media/media_pipeline_device_params.h
+++ b/chromecast/public/media/media_pipeline_device_params.h
@@ -55,8 +55,20 @@ struct MediaPipelineDeviceParams {
         audio_type(audio_type_in),
         task_runner(task_runner_in) {}
 
+  // |device_id_in| should be from media/audio/audio_device_description.h or
+  // chromecast/media/base/audio_device_ids.h
+  MediaPipelineDeviceParams(MediaSyncType sync_type_in,
+                            AudioStreamType audio_type_in,
+                            const std::string& device_id_in,
+                            TaskRunner* task_runner_in)
+      : sync_type(sync_type_in),
+        audio_type(audio_type_in),
+        device_id(device_id_in),
+        task_runner(task_runner_in) {}
+
   const MediaSyncType sync_type;
   const AudioStreamType audio_type;
+  const std::string device_id;
 
   // task_runner allows backend implementations to post tasks to the media
   // thread.  Since all calls from cast_shell into the backend are made on