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diff --git a/dom/media/mediacontrol/MediaControlKeySource.h b/dom/media/mediacontrol/MediaControlKeySource.h
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+++ b/dom/media/mediacontrol/MediaControlKeySource.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_MEDIACONTROLKEYSOURCE_H_
+#define DOM_MEDIA_MEDIACONTROL_MEDIACONTROLKEYSOURCE_H_
+
+#include "mozilla/dom/MediaControllerBinding.h"
+#include "mozilla/dom/MediaMetadata.h"
+#include "mozilla/dom/MediaSession.h"
+#include "mozilla/dom/MediaSessionBinding.h"
+#include "nsISupportsImpl.h"
+#include "nsTArray.h"
+
+namespace mozilla::dom {
+
+// This is used to store seek related properties from MediaSessionActionDetails.
+// However, currently we have no plan to support `seekOffset`.
+// https://w3c.github.io/mediasession/#the-mediasessionactiondetails-dictionary
+struct SeekDetails {
+  SeekDetails() = default;
+  explicit SeekDetails(double aSeekTime) : mSeekTime(aSeekTime) {}
+  SeekDetails(double aSeekTime, bool aFastSeek)
+      : mSeekTime(aSeekTime), mFastSeek(aFastSeek) {}
+  double mSeekTime = 0.0;
+  bool mFastSeek = false;
+};
+
+struct MediaControlAction {
+  MediaControlAction() = default;
+  explicit MediaControlAction(MediaControlKey aKey) : mKey(aKey) {}
+  MediaControlAction(MediaControlKey aKey, const SeekDetails& aDetails)
+      : mKey(aKey), mDetails(Some(aDetails)) {}
+  MediaControlKey mKey = MediaControlKey::EndGuard_;
+  Maybe<SeekDetails> mDetails;
+};
+
+/**
+ * MediaControlKeyListener is a pure interface, which is used to monitor
+ * MediaControlKey, we can add it onto the MediaControlKeySource,
+ * and then everytime when the media key events occur, `OnActionPerformed` will
+ * be called so that we can do related handling.
+ */
+class MediaControlKeyListener {
+ public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+  MediaControlKeyListener() = default;
+
+  virtual void OnActionPerformed(const MediaControlAction& aAction) = 0;
+
+ protected:
+  virtual ~MediaControlKeyListener() = default;
+};
+
+/**
+ * MediaControlKeyHandler is used to operate media controller by corresponding
+ * received media control key events.
+ */
+class MediaControlKeyHandler final : public MediaControlKeyListener {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(MediaControlKeyHandler, override)
+  void OnActionPerformed(const MediaControlAction& aAction) override;
+
+ private:
+  virtual ~MediaControlKeyHandler() = default;
+};
+
+/**
+ * MediaControlKeySource is an abstract class which is used to implement
+ * transporting media control keys event to all its listeners when media keys
+ * event happens.
+ */
+class MediaControlKeySource {
+ public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+  MediaControlKeySource();
+
+  using MediaKeysArray = nsTArray<MediaControlKey>;
+
+  virtual void AddListener(MediaControlKeyListener* aListener);
+  virtual void RemoveListener(MediaControlKeyListener* aListener);
+  size_t GetListenersNum() const;
+
+  // Return true if the initialization of the source succeeds, and inherited
+  // sources should implement this method to handle the initialization fails.
+  virtual bool Open() = 0;
+  virtual void Close();
+  virtual bool IsOpened() const = 0;
+
+  /**
+   * All following `SetXXX()` functions are used to update the playback related
+   * properties change from a specific tab, which can represent the playback
+   * status for Firefox instance. Even if we have multiple tabs playing media at
+   * the same time, we would only update information from one of that tabs that
+   * would be done by `MediaControlService`.
+   */
+  virtual void SetPlaybackState(MediaSessionPlaybackState aState);
+  virtual MediaSessionPlaybackState GetPlaybackState() const;
+
+  // Override this method if the event source needs to handle the metadata.
+  virtual void SetMediaMetadata(const MediaMetadataBase& aMetadata) {}
+
+  // Set the supported media keys which the event source can use to determine
+  // what kinds of buttons should be shown on the UI.
+  virtual void SetSupportedMediaKeys(const MediaKeysArray& aSupportedKeys) = 0;
+
+  // Override these methods if the inherited key source want to know the change
+  // for following attributes. For example, GeckoView would use these methods
+  // to notify change to the embedded application.
+  virtual void SetEnableFullScreen(bool aIsEnabled){};
+  virtual void SetEnablePictureInPictureMode(bool aIsEnabled){};
+  virtual void SetPositionState(const PositionState& aState){};
+
+ protected:
+  virtual ~MediaControlKeySource() = default;
+  nsTArray<RefPtr<MediaControlKeyListener>> mListeners;
+  MediaSessionPlaybackState mPlaybackState;
+};
+
+}  // namespace mozilla::dom
+
+#endif