Add a simple, safe gain PostProcessor.

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

Index: chromecast/media/cma/backend/alsa/post_processors/governor.cc
diff --git a/chromecast/media/cma/backend/alsa/post_processors/governor.cc b/chromecast/media/cma/backend/alsa/post_processors/governor.cc
index 832999660b1ff7b517ab08a25681bd2ef3f147df..1718ca8120e2674fc8f1345a099234fb056f5b62 100644
--- a/chromecast/media/cma/backend/alsa/post_processors/governor.cc
+++ b/chromecast/media/cma/backend/alsa/post_processors/governor.cc
@@ -75,10 +75,3 @@ void Governor::SetSlewTimeMsForTest(int 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));
-}