Revert of Move smoothing filter to common audio.

webrtc/common_audio/mocks/mock_smoothing_filter.h

Index: webrtc/common_audio/mocks/mock_smoothing_filter.h
diff --git a/webrtc/common_audio/mocks/mock_smoothing_filter.h b/webrtc/common_audio/mocks/mock_smoothing_filter.h
deleted file mode 100644
index 6b2991b22f91d736fa1e5849fc94d5b8573716db..0000000000000000000000000000000000000000
--- a/webrtc/common_audio/mocks/mock_smoothing_filter.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_COMMON_AUDIO_MOCKS_MOCK_SMOOTHING_FILTER_H_
-#define WEBRTC_COMMON_AUDIO_MOCKS_MOCK_SMOOTHING_FILTER_H_
-
-#include "webrtc/common_audio/smoothing_filter.h"
-#include "webrtc/test/gmock.h"
-
-namespace webrtc {
-
-class MockSmoothingFilter : public SmoothingFilter {
- public:
-  MOCK_METHOD1(AddSample, void(float));
-  MOCK_CONST_METHOD0(GetAverage, rtc::Optional<float>());
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_COMMON_AUDIO_MOCKS_MOCK_SMOOTHING_FILTER_H_