Add an initial revision of an audio server.

services/media/audio/platform/generic/mixers/no_op.h

+// Copyright 2015 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.
+
+#ifndef SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXERS_NO_OP_H_
+#define SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXERS_NO_OP_H_
+
+#include "services/media/audio/platform/generic/mixer.h"
+
+namespace mojo {
+namespace media {
+namespace audio {
+namespace mixers {
+
+class NoOp : public Mixer {
+ public:
+  bool Mix(void*       dst,
+           uint32_t    dst_frames,
+           uint32_t*   dst_offset,
+           const void* src,
+           uint32_t    frac_src_frames,
+           uint32_t*   frac_src_offset,
+           uint32_t    frac_step_size,
+           bool        accumulate) override;
+};
+
+}  // namespace mixers
+}  // namespace audio
+}  // namespace media
+}  // namespace mojo
+
+#endif  // SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXERS_NO_OP_H_