Add a simple, safe gain PostProcessor.

chromecast/media/cma/backend/alsa/cast_media_shlib.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <alsa/asoundlib.h>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
@@ skipping 180 matching lines @@
 }
 
 void CastMediaShlib::AddLoopbackAudioObserver(LoopbackAudioObserver* observer) {
   StreamMixerAlsa::Get()->AddLoopbackAudioObserver(observer);
 }
 
 void CastMediaShlib::RemoveLoopbackAudioObserver(
     LoopbackAudioObserver* observer) {
   StreamMixerAlsa::Get()->RemoveLoopbackAudioObserver(observer);
 }
-void SetPostProcessorConfig(const std::string& name,
-                            const std::string& config) {
+
+void CastMediaShlib::SetPostProcessorConfig(const std::string& name,
+                                            const std::string& config) {
   StreamMixerAlsa::Get()->SetPostProcessorConfig(name, config);
 }
 
 }  // namespace media
 }  // namespace chromecast