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diff --git a/dom/media/mediacontrol/AudioFocusManager.h b/dom/media/mediacontrol/AudioFocusManager.h
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+++ b/dom/media/mediacontrol/AudioFocusManager.h
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_MEDIA_MEDIACONTROL_AUDIOFOCUSMANAGER_H_
+#define DOM_MEDIA_MEDIACONTROL_AUDIOFOCUSMANAGER_H_
+
+#include "base/basictypes.h"
+#include "nsTArray.h"
+#include "VideoUtils.h"
+
+namespace mozilla::dom {
+
+class IMediaController;
+class MediaControlService;
+
+/**
+ * AudioFocusManager is used to assign the audio focus to different requester
+ * and decide which requester can own audio focus when audio competing happens.
+ * When the audio competing happens, the last request would be a winner who can
+ * still own the audio focus, and all the other requesters would lose the audio
+ * focus. Now MediaController is the onlt requester, it would request the audio
+ * focus when it becomes audible and revoke the audio focus when the controller
+ * is no longer active.
+ */
+class AudioFocusManager {
+ public:
+  void RequestAudioFocus(IMediaController* aController);
+  void RevokeAudioFocus(IMediaController* aController);
+
+  explicit AudioFocusManager() = default;
+  ~AudioFocusManager();
+
+  uint32_t GetAudioFocusNums() const;
+
+ private:
+  friend class MediaControlService;
+  // Return true if we manage audio focus by clearing other controllers owning
+  // audio focus before assigning audio focus to the new controller.
+  bool ClearFocusControllersIfNeeded();
+
+  void CreateTimerForUpdatingTelemetry();
+  // This would check if user has managed audio focus by themselves and update
+  // the result to telemetry. This method should only be called from timer.
+  void UpdateTelemetryDataFromTimer(uint32_t aPrevFocusNum,
+                                    uint64_t aPrevActiveControllerNum);
+
+  nsTArray<RefPtr<IMediaController>> mOwningFocusControllers;
+  RefPtr<SimpleTimer> mTelemetryTimer;
+};
+
+}  // namespace mozilla::dom
+
+#endif  //  DOM_MEDIA_MEDIACONTROL_AUDIOFOCUSMANAGER_H_