Add a simple, safe gain PostProcessor.

chromecast/media/cma/backend/alsa/post_processors/governor.cc

 // Copyright 2017 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 "chromecast/media/cma/backend/alsa/post_processors/governor.h"
 
 #include <memory>
 #include <string>
 
 #include "base/logging.h"
@@ skipping 57 matching lines @@
   }
   return 1.0;
 }
 
 void Governor::SetSlewTimeMsForTest(int slew_time_ms) {
   slew_volume_.SetMaxSlewTimeMs(slew_time_ms);
 }
 
 }  // namespace media
 }  // namespace chromecast
-
-chromecast::media::AudioPostProcessor* AudioPostProcessorShlib_Create(
-    const std::string& config,
-    int channels) {
-  return static_cast<chromecast::media::AudioPostProcessor*>(
-      new chromecast::media::Governor(config, channels));
-}