diff --git a/dom/media/webrtc/MediaEngineTabVideoSource.cpp b/dom/media/webrtc/MediaEngineTabVideoSource.cpp
index ec21fa070e47..7508ac839a62 100644
--- a/dom/media/webrtc/MediaEngineTabVideoSource.cpp
+++ b/dom/media/webrtc/MediaEngineTabVideoSource.cpp
@@ -119,6 +119,17 @@ MediaEngineTabVideoSource::InitRunnable::Run()
   return NS_OK;
 }
 
+nsresult
+MediaEngineTabVideoSource::DestroyRunnable::Run()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  mVideoSource->mWindow = nullptr;
+  mVideoSource->mTabSource = nullptr;
+
+  return NS_OK;
+}
+
 void
 MediaEngineTabVideoSource::GetName(nsAString_internal& aName) const
 {
@@ -193,6 +204,8 @@ nsresult
 MediaEngineTabVideoSource::Deallocate(AllocationHandle* aHandle)
 {
   MOZ_ASSERT(!aHandle);
+  NS_DispatchToMainThread(do_AddRef(new DestroyRunnable(this)));
+
   {
     MonitorAutoLock mon(mMonitor);
     mState = kReleased;
diff --git a/dom/media/webrtc/MediaEngineTabVideoSource.h b/dom/media/webrtc/MediaEngineTabVideoSource.h
index d4d30a811314..d11bd7765af8 100644
--- a/dom/media/webrtc/MediaEngineTabVideoSource.h
+++ b/dom/media/webrtc/MediaEngineTabVideoSource.h
@@ -81,6 +81,13 @@ class MediaEngineTabVideoSource : public MediaEngineVideoSource, nsIDOMEventList
       RefPtr<MediaEngineTabVideoSource> mVideoSource;
     };
 
+    class DestroyRunnable : public Runnable {
+    public:
+      explicit DestroyRunnable(MediaEngineTabVideoSource* videoSource) : mVideoSource(videoSource) {}
+      NS_IMETHOD Run();
+      RefPtr<MediaEngineTabVideoSource> mVideoSource;
+    };
+
 protected:
     ~MediaEngineTabVideoSource() {}