Revert onrender change (#49333)

This reverts #49214 and
#48758.

#49214 appears to cause a Flutter
Gold diff during the engine roll. See
flutter/flutter#140434 for an example. It's
unclear to me whether this is an expected diff and should be approved or
unexpected and should be reverting, so reverting to the last previous
rollable state.

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I added new tests to check the change I am making or feature I am
adding, or the PR is [test-exempt]. See [testing the engine] for
instructions on writing and running engine tests.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I signed the [CLA].
- [ ] All existing and new tests are passing.

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on [Discord].

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Author: cbracken

lib/web_ui/lib/platform_dispatcher.dart

@@ -80,7 +80,7 @@ abstract class PlatformDispatcher {
 
   void scheduleFrame();
 
-  Future<void> render(Scene scene, [FlutterView view]);
+  void render(Scene scene, [FlutterView view]);
 
   AccessibilityFeatures get accessibilityFeatures;
 

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

@@ -364,7 +364,7 @@ class HtmlViewEmbedder {
     sceneHost.append(_svgPathDefs!);
   }
 
-  Future<void> submitFrame() async {
+  void submitFrame() {
     final ViewListDiffResult? diffResult =
         (_activeCompositionOrder.isEmpty || _compositionOrder.isEmpty)
             ? null
@@ -388,7 +388,7 @@ class HtmlViewEmbedder {
             _context.pictureRecorders[pictureRecorderIndex].endRecording());
         pictureRecorderIndex++;
       }
-      await rasterizer.rasterizeToCanvas(overlay, pictures);
+      rasterizer.rasterizeToCanvas(overlay, pictures);
     }
     for (final CkPictureRecorder recorder
         in _context.pictureRecordersCreatedDuringPreroll) {
@@ -443,7 +443,8 @@ class HtmlViewEmbedder {
           sceneHost.insertBefore(platformViewRoot, elementToInsertBefore);
           final RenderCanvas? overlay = _overlays[viewId];
           if (overlay != null) {
-            sceneHost.insertBefore(overlay.htmlElement, elementToInsertBefore);
+            sceneHost.insertBefore(
+                overlay.htmlElement, elementToInsertBefore);
           }
         } else {
           final DomElement platformViewRoot = _viewClipChains[viewId]!.root;
@@ -653,8 +654,6 @@ class HtmlViewEmbedder {
       }
     }
     _svgClipDefs.clear();
-    _svgPathDefs?.remove();
-    _svgPathDefs = null;
   }
 
   static void removeElement(DomElement element) {

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.
-  Future<void> draw(LayerTree layerTree) async {
+  void draw(LayerTree layerTree) {
     final ui.Size frameSize = view.physicalSize;
     if (frameSize.isEmpty) {
       // Available drawing area is empty. Skip drawing.
@@ -49,10 +49,10 @@ class Rasterizer {
     compositorFrame.raster(layerTree, ignoreRasterCache: true);
 
     sceneHost.prepend(renderCanvasFactory.baseCanvas.htmlElement);
-    await rasterizeToCanvas(renderCanvasFactory.baseCanvas,
+    rasterizeToCanvas(renderCanvasFactory.baseCanvas,
         <CkPicture>[pictureRecorder.endRecording()]);
 
-    await viewEmbedder.submitFrame();
+    viewEmbedder.submitFrame();
   }
 
   /// Disposes of this rasterizer.

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

@@ -85,7 +85,6 @@ class CanvasKitRenderer implements Renderer {
           viewManager.onViewDisposed.listen(_onViewDisposed);
       _instance = this;
     }();
-    registerHotRestartListener(dispose);
     return _initialized;
   }
 
@@ -403,7 +402,7 @@ class CanvasKitRenderer implements Renderer {
     CkParagraphBuilder(style);
 
   @override
-  Future<void> renderScene(ui.Scene scene, ui.FlutterView view) async {
+  void renderScene(ui.Scene scene, ui.FlutterView view) {
     // "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.
@@ -418,7 +417,7 @@ class CanvasKitRenderer implements Renderer {
         "Unable to render to a view which hasn't been registered");
     final Rasterizer rasterizer = _rasterizers[view.viewId]!;
 
-    await rasterizer.draw((scene as LayerScene).layerTree);
+    rasterizer.draw((scene as LayerScene).layerTree);
     frameTimingsOnRasterFinish();
   }
 
@@ -452,7 +451,6 @@ class CanvasKitRenderer implements Renderer {
       rasterizer.dispose();
     }
     _rasterizers.clear();
-    clearFragmentProgramCache();
   }
 
   @override

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

@@ -115,18 +115,22 @@ class Surface {
     _surface!.flush();
 
     if (browserSupportsCreateImageBitmap) {
-      JSObject bitmapSource;
+      DomImageBitmap bitmap;
       if (Surface.offscreenCanvasSupported) {
-        bitmapSource = _offscreenCanvas! as JSObject;
+        bitmap = (await createImageBitmap(_offscreenCanvas! as JSObject, (
+          x: 0,
+          y: _pixelHeight - frameSize.height.toInt(),
+          width: frameSize.width.toInt(),
+          height: frameSize.height.toInt(),
+        )).toDart)! as DomImageBitmap;
       } else {
-        bitmapSource = _canvasElement! as JSObject;
+        bitmap = (await createImageBitmap(_canvasElement! as JSObject, (
+          x: 0,
+          y: _pixelHeight - frameSize.height.toInt(),
+          width: frameSize.width.toInt(),
+          height: frameSize.height.toInt()
+        )).toDart)! as DomImageBitmap;
       }
-      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

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

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

@@ -31,7 +31,6 @@ class HtmlRenderer implements Renderer {
       // to make the unpacking happen while we are waiting for network requests.
       lineLookup;
     });
-    registerHotRestartListener(clearFragmentProgramCache);
 
     _instance = this;
   }
@@ -324,7 +323,7 @@ class HtmlRenderer implements Renderer {
     CanvasParagraphBuilder(style as EngineParagraphStyle);
 
   @override
-  Future<void> renderScene(ui.Scene scene, ui.FlutterView view) async {
+  void renderScene(ui.Scene scene, ui.FlutterView view) {
     final EngineFlutterView implicitView = EnginePlatformDispatcher.instance.implicitView!;
     implicitView.dom.setScene((scene as SurfaceScene).webOnlyRootElement!);
     frameTimingsOnRasterFinish();

lib/web_ui/lib/src/engine/platform_dispatcher.dart

@@ -213,10 +213,6 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     }
   }
 
-  /// A set of views which have rendered in the current `onBeginFrame` or
-  /// `onDrawFrame` scope.
-  Set<ui.FlutterView>? _viewsRenderedInCurrentFrame;
-
   /// A callback invoked when any window begins a frame.
   ///
   /// A callback that is invoked to notify the application that it is an
@@ -239,9 +235,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   /// Engine code should use this method instead of the callback directly.
   /// Otherwise zones won't work properly.
   void invokeOnBeginFrame(Duration duration) {
-    _viewsRenderedInCurrentFrame = <ui.FlutterView>{};
     invoke1<Duration>(_onBeginFrame, _onBeginFrameZone, duration);
-    _viewsRenderedInCurrentFrame = null;
   }
 
   /// A callback that is invoked for each frame after [onBeginFrame] has
@@ -262,9 +256,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   /// Engine code should use this method instead of the callback directly.
   /// Otherwise zones won't work properly.
   void invokeOnDrawFrame() {
-    _viewsRenderedInCurrentFrame = <ui.FlutterView>{};
     invoke(_onDrawFrame, _onDrawFrameZone);
-    _viewsRenderedInCurrentFrame = null;
   }
 
   /// A callback that is invoked when pointer data is available.
@@ -761,23 +753,14 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   ///  * [RendererBinding], the Flutter framework class which manages layout and
   ///    painting.
   @override
-  Future<void> render(ui.Scene scene, [ui.FlutterView? view]) async {
+  void render(ui.Scene scene, [ui.FlutterView? view]) {
     assert(view != null || implicitView != null,
         'Calling render without a FlutterView');
     if (view == null && implicitView == null) {
       // If there is no view to render into, then this is a no-op.
       return;
     }
-    final ui.FlutterView viewToRender = view ?? implicitView!;
-
-    // Only render in an `onDrawFrame` or `onBeginFrame` scope. This is checked
-    // by checking if the `_viewsRenderedInCurrentFrame` is non-null and this
-    // view hasn't been rendered already in this scope.
-    final bool shouldRender =
-        _viewsRenderedInCurrentFrame?.add(viewToRender) ?? false;
-    if (shouldRender) {
-      await renderer.renderScene(scene, viewToRender);
-    }
+    renderer.renderScene(scene, view ?? implicitView!);
   }
 
   /// Additional accessibility features that may be enabled by the platform.
@@ -1292,8 +1275,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   String get defaultRouteName {
     // TODO(mdebbar): What should we do in multi-view mode?
     //                https://github.com/flutter/flutter/issues/139174
-    return _defaultRouteName ??=
-        implicitView?.browserHistory.currentPath ?? '/';
+    return _defaultRouteName ??= implicitView?.browserHistory.currentPath ?? '/';
   }
 
   /// Lazily initialized when the `defaultRouteName` getter is invoked.

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

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

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

@@ -349,7 +349,6 @@ class SkwasmRenderer implements Renderer {
   FutureOr<void> initialize() {
     surface = SkwasmSurface();
     sceneView = EngineSceneView(SkwasmPictureRenderer(surface));
-    registerHotRestartListener(clearFragmentProgramCache);
   }
 
   @override