Futurize more

lib/web_ui/lib/src/engine/canvaskit/rasterizer.dart

@@ -30,7 +30,7 @@ class Rasterizer {
 
   /// Creates a new frame from this rasterizer's surface, draws the given
   /// [LayerTree] into it, and then submits the frame.
-  void draw(LayerTree layerTree) {
+  Future<void> draw(LayerTree layerTree) async {
     final ui.Size frameSize = view.physicalSize;
     if (frameSize.isEmpty) {
       // Available drawing area is empty. Skip drawing.
@@ -49,7 +49,7 @@ class Rasterizer {
     compositorFrame.raster(layerTree, ignoreRasterCache: true);
 
     sceneHost.prepend(renderCanvasFactory.baseCanvas.htmlElement);
-    rasterizeToCanvas(renderCanvasFactory.baseCanvas,
+    await rasterizeToCanvas(renderCanvasFactory.baseCanvas,
         <CkPicture>[pictureRecorder.endRecording()]);
 
     viewEmbedder.submitFrame();

lib/web_ui/lib/src/engine/canvaskit/renderer.dart

@@ -402,7 +402,7 @@ class CanvasKitRenderer implements Renderer {
     CkParagraphBuilder(style);
 
   @override
-  void renderScene(ui.Scene scene, ui.FlutterView view) {
+  Future<void> renderScene(ui.Scene scene, ui.FlutterView view) async {
     // "Build finish" and "raster start" happen back-to-back because we
     // render on the same thread, so there's no overhead from hopping to
     // another thread.
@@ -417,7 +417,7 @@ class CanvasKitRenderer implements Renderer {
         "Unable to render to a view which hasn't been registered");
     final Rasterizer rasterizer = _rasterizers[view.viewId]!;
 
-    rasterizer.draw((scene as LayerScene).layerTree);
+    await rasterizer.draw((scene as LayerScene).layerTree);
     frameTimingsOnRasterFinish();
   }
 

lib/web_ui/lib/src/engine/canvaskit/surface.dart

@@ -115,22 +115,18 @@ class Surface {
     _surface!.flush();
 
     if (browserSupportsCreateImageBitmap) {
-      DomImageBitmap bitmap;
+      JSObject bitmapSource;
       if (Surface.offscreenCanvasSupported) {
-        bitmap = (await createImageBitmap(_offscreenCanvas! as JSObject, (
-          x: 0,
-          y: _pixelHeight - frameSize.height.toInt(),
-          width: frameSize.width.toInt(),
-          height: frameSize.height.toInt(),
-        )).toDart)! as DomImageBitmap;
+        bitmapSource = _offscreenCanvas! as JSObject;
       } else {
-        bitmap = (await createImageBitmap(_canvasElement! as JSObject, (
-          x: 0,
-          y: _pixelHeight - frameSize.height.toInt(),
-          width: frameSize.width.toInt(),
-          height: frameSize.height.toInt()
-        )).toDart)! as DomImageBitmap;
+        bitmapSource = _canvasElement! as JSObject;
       }
+      final DomImageBitmap bitmap = await createImageBitmap(bitmapSource, (
+        x: 0,
+        y: _pixelHeight - frameSize.height.toInt(),
+        width: frameSize.width.toInt(),
+        height: frameSize.height.toInt(),
+      ));
       canvas.render(bitmap);
     } else {
       // If the browser doesn't support `createImageBitmap` (e.g. Safari 14)

lib/web_ui/lib/src/engine/dom.dart

@@ -210,14 +210,16 @@ external JSPromise<JSAny?> _createImageBitmap2(
   JSNumber width,
   JSNumber height,
 );
-JSPromise<JSAny?> createImageBitmap(JSAny source,
+Future<DomImageBitmap> createImageBitmap(JSAny source,
     [({int x, int y, int width, int height})? bounds]) {
+  JSPromise<JSAny?> jsPromise;
   if (bounds != null) {
-    return _createImageBitmap2(source, bounds.x.toJS, bounds.y.toJS,
+    jsPromise = _createImageBitmap2(source, bounds.x.toJS, bounds.y.toJS,
         bounds.width.toJS, bounds.height.toJS);
   } else {
-    return _createImageBitmap1(source);
+    jsPromise = _createImageBitmap1(source);
   }
+  return js_util.promiseToFuture<DomImageBitmap>(jsPromise);
 }
 
 @JS()

lib/web_ui/lib/src/engine/html/renderer.dart

@@ -323,7 +323,7 @@ class HtmlRenderer implements Renderer {
     CanvasParagraphBuilder(style as EngineParagraphStyle);
 
   @override
-  void renderScene(ui.Scene scene, ui.FlutterView view) {
+  Future<void> renderScene(ui.Scene scene, ui.FlutterView view) async {
     final EngineFlutterView implicitView = EnginePlatformDispatcher.instance.implicitView!;
     implicitView.dom.setScene((scene as SurfaceScene).webOnlyRootElement!);
     frameTimingsOnRasterFinish();

lib/web_ui/lib/src/engine/renderer.dart

@@ -222,5 +222,5 @@ abstract class Renderer {
 
   ui.ParagraphBuilder createParagraphBuilder(ui.ParagraphStyle style);
 
-  FutureOr<void> renderScene(ui.Scene scene, ui.FlutterView view);
+  Future<void> renderScene(ui.Scene scene, ui.FlutterView view);
 }

lib/web_ui/lib/src/engine/skwasm/skwasm_stub/renderer.dart

@@ -150,7 +150,7 @@ class SkwasmRenderer implements Renderer {
   }
 
   @override
-  void renderScene(ui.Scene scene, ui.FlutterView view) {
+  Future<void> renderScene(ui.Scene scene, ui.FlutterView view) {
     throw UnimplementedError('Skwasm not implemented on this platform.');
   }
 

lib/web_ui/test/engine/semantics/semantics_test.dart

@@ -33,6 +33,7 @@ void main() {
 
 Future<void> testMain() async {
   await bootstrapAndRunApp();
+  setUpRenderingForTests();
   runSemanticsTests();
 }