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diff --git a/dom/media/mediacontrol/ContentMediaController.h b/dom/media/mediacontrol/ContentMediaController.h
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+++ b/dom/media/mediacontrol/ContentMediaController.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_CONTENTMEDIACONTROLLER_H_
+#define DOM_MEDIA_MEDIACONTROL_CONTENTMEDIACONTROLLER_H_
+
+#include "MediaControlKeySource.h"
+#include "MediaStatusManager.h"
+
+namespace mozilla::dom {
+
+class BrowsingContext;
+
+/**
+ * ContentMediaControlKeyReceiver is an interface which is used to receive media
+ * control key sent from the chrome process.
+ */
+class ContentMediaControlKeyReceiver {
+ public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  // Return nullptr if the top level browsing context is no longer alive.
+  static ContentMediaControlKeyReceiver* Get(BrowsingContext* aBC);
+
+  // Use this method to handle the event from `ContentMediaAgent`.
+  virtual void HandleMediaKey(MediaControlKey aKey) = 0;
+
+  virtual bool IsPlaying() const = 0;
+};
+
+/**
+ * ContentMediaAgent is an interface which we use to (1) propoagate media
+ * related information from the content process to the chrome process (2) act an
+ * event source to dispatch media control key to its listeners.
+ *
+ * If the media would like to know the media control key, then media MUST
+ * inherit from ContentMediaControlKeyReceiver, and register themselves to
+ * ContentMediaAgent. Whenever media control key delivers, ContentMediaAgent
+ * would notify all its receivers. In addition, whenever controlled media
+ * changes its playback status or audible state, they should update their status
+ * update via ContentMediaAgent.
+ */
+class ContentMediaAgent : public IMediaInfoUpdater {
+ public:
+  // Return nullptr if the top level browsing context is no longer alive.
+  static ContentMediaAgent* Get(BrowsingContext* aBC);
+
+  // IMediaInfoUpdater Methods
+  void NotifyMediaPlaybackChanged(uint64_t aBrowsingContextId,
+                                  MediaPlaybackState aState) override;
+  void NotifyMediaAudibleChanged(uint64_t aBrowsingContextId,
+                                 MediaAudibleState aState) override;
+  void SetIsInPictureInPictureMode(uint64_t aBrowsingContextId,
+                                   bool aIsInPictureInPictureMode) override;
+  void SetDeclaredPlaybackState(uint64_t aBrowsingContextId,
+                                MediaSessionPlaybackState aState) override;
+  void NotifySessionCreated(uint64_t aBrowsingContextId) override;
+  void NotifySessionDestroyed(uint64_t aBrowsingContextId) override;
+  void UpdateMetadata(uint64_t aBrowsingContextId,
+                      const Maybe<MediaMetadataBase>& aMetadata) override;
+  void EnableAction(uint64_t aBrowsingContextId,
+                    MediaSessionAction aAction) override;
+  void DisableAction(uint64_t aBrowsingContextId,
+                     MediaSessionAction aAction) override;
+  void NotifyMediaFullScreenState(uint64_t aBrowsingContextId,
+                                  bool aIsInFullScreen) override;
+  void UpdatePositionState(uint64_t aBrowsingContextId,
+                           const PositionState& aState) override;
+
+  // Use these methods to register/unregister `ContentMediaControlKeyReceiver`
+  // in order to listen to media control key events.
+  virtual void AddReceiver(ContentMediaControlKeyReceiver* aReceiver) = 0;
+  virtual void RemoveReceiver(ContentMediaControlKeyReceiver* aReceiver) = 0;
+};
+
+/**
+ * ContentMediaController exists in per inner window, which has a responsibility
+ * to update the content media state to MediaController (ContentMediaAgent) and
+ * delivers MediaControlKey to its receiver in order to control media in the
+ * content page (ContentMediaControlKeyReceiver).
+ */
+class ContentMediaController final : public ContentMediaAgent,
+                                     public ContentMediaControlKeyReceiver {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(ContentMediaController, override)
+
+  explicit ContentMediaController(uint64_t aId);
+  // ContentMediaAgent methods
+  void AddReceiver(ContentMediaControlKeyReceiver* aListener) override;
+  void RemoveReceiver(ContentMediaControlKeyReceiver* aListener) override;
+
+  // ContentMediaControlKeyReceiver method
+  void HandleMediaKey(MediaControlKey aKey) override;
+
+ private:
+  ~ContentMediaController() = default;
+
+  // We don't need this method, so make it as private and simply return false.
+  virtual bool IsPlaying() const override { return false; }
+
+  void PauseOrStopMedia();
+
+  nsTArray<RefPtr<ContentMediaControlKeyReceiver>> mReceivers;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // DOM_MEDIA_MEDIACONTROL_CONTENTMEDIACONTROLLER_H_