diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index d8d5688e6d7e..0b5551a48e04 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -1683,6 +1683,9 @@ bool
 ContentChild::RecvNotifyGMPsChanged()
 {
   GMPDecoderModule::UpdateUsableCodecs();
+  MOZ_ASSERT(NS_IsMainThread());
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  obs->NotifyObservers(nullptr, "gmp-changed", nullptr);
   return true;
 }
 
diff --git a/dom/media/eme/MediaKeySystemAccessManager.cpp b/dom/media/eme/MediaKeySystemAccessManager.cpp
index 502e4a98c912..820cabf0e6af 100644
--- a/dom/media/eme/MediaKeySystemAccessManager.cpp
+++ b/dom/media/eme/MediaKeySystemAccessManager.cpp
@@ -263,7 +263,7 @@ MediaKeySystemAccessManager::Observe(nsISupports* aSubject,
 {
   EME_LOG("MediaKeySystemAccessManager::Observe %s", aTopic);
 
-  if (!strcmp(aTopic, "gmp-path-added")) {
+  if (!strcmp(aTopic, "gmp-changed")) {
     nsTArray<PendingRequest> requests(Move(mRequests));
     // Retry all pending requests, but this time fail if the CDM is not installed.
     for (PendingRequest& request : requests) {
@@ -296,7 +296,7 @@ MediaKeySystemAccessManager::EnsureObserversAdded()
   if (NS_WARN_IF(!obsService)) {
     return false;
   }
-  mAddedObservers = NS_SUCCEEDED(obsService->AddObserver(this, "gmp-path-added", false));
+  mAddedObservers = NS_SUCCEEDED(obsService->AddObserver(this, "gmp-changed", false));
   return mAddedObservers;
 }
 
@@ -313,7 +313,7 @@ MediaKeySystemAccessManager::Shutdown()
   if (mAddedObservers) {
     nsCOMPtr<nsIObserverService> obsService = mozilla::services::GetObserverService();
     if (obsService) {
-      obsService->RemoveObserver(this, "gmp-path-added");
+      obsService->RemoveObserver(this, "gmp-changed");
       mAddedObservers = false;
     }
   }
diff --git a/dom/media/gmp/GMPServiceParent.cpp b/dom/media/gmp/GMPServiceParent.cpp
index d799db4d5c00..11ff331b80bb 100644
--- a/dom/media/gmp/GMPServiceParent.cpp
+++ b/dom/media/gmp/GMPServiceParent.cpp
@@ -1107,7 +1107,6 @@ GeckoMediaPluginServiceParent::AddOnGMPThread(nsString aDirectory)
         MutexAutoLock lock(self->mMutex);
         self->mPlugins.AppendElement(gmp);
       }
-      NS_DispatchToMainThread(new NotifyObserversTask("gmp-path-added"), NS_DISPATCH_NORMAL);
     },
     [dir]() -> void {
       LOGD(("%s::%s: %s Failed", __CLASS__, __FUNCTION__, dir.get()));