support graphics device being fed in

src/framework/application.js

@@ -108,6 +108,9 @@ class Application extends AppBase {
      * handler for input.
      * @param {string} [options.scriptPrefix] - Prefix to apply to script urls before loading.
      * @param {string} [options.assetPrefix] - Prefix to apply to asset urls before loading.
+     * @param {import('../platform/graphics/graphics-device.js').GraphicsDevice} [options.graphicsDevice] - The
+     * graphics device used by the application. If not provided, a WebGl graphics device will be
+     * created.
      * @param {object} [options.graphicsDeviceOptions] - Options object that is passed into the
      * {@link GraphicsDevice} constructor.
      * @param {string[]} [options.scriptsOrder] - Scripts in order of loading first.
@@ -123,7 +126,7 @@ class Application extends AppBase {
 
         const appOptions = new AppOptions();
 
-        appOptions.graphicsDevice = this.createDevice(canvas, options);
+        appOptions.graphicsDevice = options.graphicsDevice ?? this.createDevice(canvas, options);
         this.addComponentSystems(appOptions);
         this.addResourceHandles(appOptions);