diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index f6e5f7217c7..d10de70a4fe 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -2611,7 +2611,7 @@ Navigator::RequestMediaKeySystemAccess(const nsAString& aKeySystem,
   if (!Preferences::GetBool("media.eme.enabled", false)) {
     // EME disabled by user, send notification to chrome so UI can
     // inform user.
-    MediaKeySystemAccess::NotifyObservers(aKeySystem,
+    MediaKeySystemAccess::NotifyObservers(mWindow, aKeySystem,
                                           MediaKeySystemStatus::Api_disabled);
     p->MaybeReject(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return p.forget();
@@ -2629,7 +2629,7 @@ Navigator::RequestMediaKeySystemAccess(const nsAString& aKeySystem,
       // Failed due to user disabling something, send a notification to
       // chrome, so we can show some UI to explain how the user can rectify
       // the situation.
-      MediaKeySystemAccess::NotifyObservers(aKeySystem, status);
+      MediaKeySystemAccess::NotifyObservers(mWindow, aKeySystem, status);
     }
     p->MaybeReject(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return p.forget();
diff --git a/dom/media/eme/MediaKeySystemAccess.cpp b/dom/media/eme/MediaKeySystemAccess.cpp
index 6546fefd5ec..46889f5cb04 100644
--- a/dom/media/eme/MediaKeySystemAccess.cpp
+++ b/dom/media/eme/MediaKeySystemAccess.cpp
@@ -226,7 +226,8 @@ MediaKeySystemAccess::IsSupported(const nsAString& aKeySystem,
 
 /* static */
 void
-MediaKeySystemAccess::NotifyObservers(const nsAString& aKeySystem,
+MediaKeySystemAccess::NotifyObservers(nsIDOMWindow* aWindow,
+                                      const nsAString& aKeySystem,
                                       MediaKeySystemStatus aStatus)
 {
   RequestMediaKeySystemAccessNotification data;
@@ -236,7 +237,7 @@ MediaKeySystemAccess::NotifyObservers(const nsAString& aKeySystem,
   data.ToJSON(json);
   nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
   if (obs) {
-    obs->NotifyObservers(nullptr, "mediakeys-request", json.get());
+    obs->NotifyObservers(aWindow, "mediakeys-request", json.get());
   }
 }
 
diff --git a/dom/media/eme/MediaKeySystemAccess.h b/dom/media/eme/MediaKeySystemAccess.h
index 22c74a07411..ba8feff1562 100644
--- a/dom/media/eme/MediaKeySystemAccess.h
+++ b/dom/media/eme/MediaKeySystemAccess.h
@@ -49,7 +49,8 @@ public:
   static bool IsSupported(const nsAString& aKeySystem,
                           const Sequence<MediaKeySystemOptions>& aOptions);
 
-  static void NotifyObservers(const nsAString& aKeySystem,
+  static void NotifyObservers(nsIDOMWindow* aWindow,
+                              const nsAString& aKeySystem,
                               MediaKeySystemStatus aStatus);
 
 private:
diff --git a/dom/media/eme/MediaKeys.cpp b/dom/media/eme/MediaKeys.cpp
index 34f8383fd65..e6e52742e9a 100644
--- a/dom/media/eme/MediaKeys.cpp
+++ b/dom/media/eme/MediaKeys.cpp
@@ -367,7 +367,8 @@ MediaKeys::OnCDMCreated(PromiseId aId, const nsACString& aNodeId)
     Release();
   }
 
-  MediaKeySystemAccess::NotifyObservers(mKeySystem,
+  MediaKeySystemAccess::NotifyObservers(mParent,
+                                        mKeySystem,
                                         MediaKeySystemStatus::Cdm_created);
 }