Mix to an intermediate buffer.

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:
   NoOp() : Mixer(0, 0) {}
 
-  bool Mix(void*       dst,
+  bool Mix(int32_t*    dst,
            uint32_t    dst_frames,
            uint32_t*   dst_offset,
            const void* src,
            uint32_t    frac_src_frames,
            int32_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_