Remove webrtc/sound/ subdir.

webrtc/sound/soundinputstreaminterface.cc

Index: webrtc/sound/soundinputstreaminterface.cc
diff --git a/webrtc/sound/soundinputstreaminterface.cc b/webrtc/sound/soundinputstreaminterface.cc
deleted file mode 100644
index b7bf0744ede083d6ed29b724000f181fc58fd993..0000000000000000000000000000000000000000
--- a/webrtc/sound/soundinputstreaminterface.cc
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- *  Copyright 2015 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.
- */
-
-#include "webrtc/sound/soundinputstreaminterface.h"
-namespace rtc {
-
-SoundInputStreamInterface::~SoundInputStreamInterface() {}
-
-SoundInputStreamInterface::SoundInputStreamInterface() {}
-
-}  // namespace rtc