Move smoothing filter to common audio.

webrtc/base/smoothing_filter.h

Index: webrtc/base/smoothing_filter.h
diff --git a/webrtc/modules/audio_coding/audio_network_adaptor/smoothing_filter.h b/webrtc/base/smoothing_filter.h
similarity index 86%
rename from webrtc/modules/audio_coding/audio_network_adaptor/smoothing_filter.h
rename to webrtc/base/smoothing_filter.h
index c4de7b5da5a5dc7f85b2f5e258505fb5025cb7b1..600a0d76342f068d393a5666770adbefccf8f9d1 100644
--- a/webrtc/modules/audio_coding/audio_network_adaptor/smoothing_filter.h
+++ b/webrtc/base/smoothing_filter.h
@@ -8,8 +8,8 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_SMOOTHING_FILTER_H_
-#define WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_SMOOTHING_FILTER_H_
+#ifndef WEBRTC_BASE_SMOOTHING_FILTER_H_
+#define WEBRTC_BASE_SMOOTHING_FILTER_H_
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/exp_filter.h"
@@ -51,4 +51,4 @@ class SmoothingFilterImpl final : public SmoothingFilter {
 
 }  // namespace webrtc
 
-#endif  // WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_SMOOTHING_FILTER_H_
+#endif  // WEBRTC_BASE_SMOOTHING_FILTER_H_