delete websurfaces on shutdown

interface/src/Application.h

@@ -229,7 +229,7 @@ public:
 
     qint64 getCurrentSessionRuntime() const { return _sessionRunTimer.elapsed(); }
 
-    bool isAboutToQuit() const { return _aboutToQuit; }
+    bool isAboutToQuit() const override { return _aboutToQuit; }
     bool isPhysicsEnabled() const { return _physicsEnabled; }
 
     // the isHMDMode is true whenever we use the interface from an HMD and not a standard flat display

libraries/entities-renderer/src/RenderableWebEntityItem.cpp

@@ -95,7 +95,13 @@ bool RenderableWebEntityItem::buildWebSurface(EntityTreeRenderer* renderer) {
 
     auto deleter = [](OffscreenQmlSurface* webSurface) {
         AbstractViewStateInterface::instance()->postLambdaEvent([webSurface] {
-            webSurface->deleteLater();
+            if (AbstractViewStateInterface::instance()->isAboutToQuit()) {
+                // WebEngineView may run other threads (wasapi), so they must be deleted for a clean shutdown
+                // if the application has already stopped its event loop, delete must be explicit
+                delete webSurface;
+            } else {
+                webSurface->deleteLater();
+            }
         });
     };
     _webSurface = QSharedPointer<OffscreenQmlSurface>(new OffscreenQmlSurface(), deleter);
@@ -331,6 +337,7 @@ void RenderableWebEntityItem::destroyWebSurface() {
         if (rootItem) {
             QObject* obj = rootItem->findChild<QObject*>("webEngineView");
             if (obj) {
+                // stop loading
                 QMetaObject::invokeMethod(obj, "stop");
             }
         }

libraries/render-utils/src/AbstractViewStateInterface.h

@@ -40,7 +40,9 @@ public:
 
     virtual glm::vec3 getAvatarPosition() const = 0;
 
+    virtual bool isAboutToQuit() const = 0;
     virtual void postLambdaEvent(std::function<void()> f) = 0;
+
     virtual qreal getDevicePixelRatio() = 0;
 
     virtual render::ScenePointer getMain3DScene() = 0;