Reland of https://codereview.webrtc.org/2396483002/

webrtc/modules/audio_mixer/audio_source_with_mix_status.h

Index: webrtc/modules/audio_mixer/audio_source_with_mix_status.h
diff --git a/webrtc/modules/audio_mixer/audio_source_with_mix_status.h b/webrtc/modules/audio_mixer/audio_source_with_mix_status.h
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index 0000000000000000000000000000000000000000..3489ec46ec722e7ab32fb33c38206c17f0b0a73d
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+/*
+ *  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_MODULES_AUDIO_MIXER_AUDIO_SOURCE_WITH_MIX_STATUS_H_
+#define WEBRTC_MODULES_AUDIO_MIXER_AUDIO_SOURCE_WITH_MIX_STATUS_H_
+
+#include "webrtc/modules/audio_mixer/audio_mixer_defines.h"
+
+namespace webrtc {
+
+// A class that holds a mixer participant and its mixing status.
+class AudioSourceWithMixStatus {
+ public:
+  explicit AudioSourceWithMixStatus(MixerAudioSource* audio_source);
+  ~AudioSourceWithMixStatus();
+
+  AudioSourceWithMixStatus(const AudioSourceWithMixStatus&) = default;
+
+  // Returns true if the audio source was mixed this mix iteration.
+  bool IsMixed() const;
+
+  // Returns true if the audio source was mixed previous mix
+  // iteration.
+  bool WasMixed() const;
+
+  // Updates the mixed status.
+  void SetIsMixed(const bool mixed);
+  void ResetMixedStatus();
+  MixerAudioSource* audio_source() const;
+
+ private:
+  MixerAudioSource* audio_source_ = nullptr;
+  bool is_mixed_ = false;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_MIXER_AUDIO_SOURCE_WITH_MIX_STATUS_H_