Bug 1715415 - part2 : clear the active session Id when stopping a controller. r=chunmin

As we would not deactivate the controller if we have an active session [1], clear the active session Id in order to trigger the process of deactivating controller later.

[1] https://searchfox.org/mozilla-central/rev/f351e19360729b351bfc7c1386d6e4ca4ea676e2/dom/media/mediacontrol/MediaController.cpp#352-362

Differential Revision: https://phabricator.services.mozilla.com/D117956

dom/media/mediacontrol/MediaController.cpp

@@ -170,6 +170,7 @@ void MediaController::Stop() {
   LOG("Stop");
   UpdateMediaControlActionToContentMediaIfNeeded(
       MediaControlAction(MediaControlKey::Stop));
+  MediaStatusManager::ClearActiveMediaSessionContextIdIfNeeded();
 }
 
 uint64_t MediaController::Id() const { return mTopLevelBrowsingContextId; }

dom/media/mediacontrol/MediaStatusManager.h

@@ -212,6 +212,8 @@ class MediaStatusManager : public IMediaInfoUpdater {
   // media session and owns the audio focus within a tab.
   Maybe<uint64_t> mActiveMediaSessionContextId;
 
+  void ClearActiveMediaSessionContextIdIfNeeded();
+
  private:
   nsString GetDefaultFaviconURL() const;
   nsString GetDefaultTitle() const;
@@ -221,7 +223,6 @@ class MediaStatusManager : public IMediaInfoUpdater {
 
   bool IsSessionOwningAudioFocus(uint64_t aBrowsingContextId) const;
   void SetActiveMediaSessionContextId(uint64_t aBrowsingContextId);
-  void ClearActiveMediaSessionContextIdIfNeeded();
   void HandleAudioFocusOwnerChanged(Maybe<uint64_t>& aBrowsingContextId);
 
   void NotifySupportedKeysChangedIfNeeded(uint64_t aBrowsingContextId);