Try fix typings VR

src/Engines/Extensions/engine.webVR.ts

@@ -7,16 +7,6 @@ import { Tools } from '../../Misc/tools';
 import { DomManagement } from '../../Misc/domManagement';
 
 declare module "../../Engines/engine" {
-    /**
-     * Defines the interface used by display changed events
-     */
-    export interface IDisplayChangedEventArgs {
-        /** Gets the vrDisplay object (if any) */
-        vrDisplay: Nullable<any>;
-        /** Gets a boolean indicating if webVR is supported */
-        vrSupported: boolean;
-    }
-
     export interface Engine {
         /** @hidden */
         _vrDisplay: any;

src/Engines/engine.ts

@@ -8,7 +8,6 @@ import { Camera } from "../Cameras/camera";
 import { Scene } from "../scene";
 import { Matrix, Color3, Color4, Viewport, Vector4 } from "../Maths/math";
 import { Scalar } from "../Maths/math.scalar";
-import { IDisplayChangedEventArgs } from "../Engines/engine";
 import { VertexBuffer } from "../Meshes/buffer";
 import { UniformBuffer } from "../Materials/uniformBuffer";
 import { Effect, EffectCreationOptions, EffectFallbacks } from "../Materials/effect";
@@ -230,6 +229,16 @@ export interface EngineOptions extends WebGLContextAttributes {
 }
 
 /**
+ * Defines the interface used by display changed events
+ */
+export interface IDisplayChangedEventArgs {
+    /** Gets the vrDisplay object (if any) */
+    vrDisplay: Nullable<any>;
+    /** Gets a boolean indicating if webVR is supported */
+    vrSupported: boolean;
+}
+
+/**
  * The engine class is responsible for interfacing with all lower-level APIs such as WebGL and Audio
  */
 export class Engine {