[canvaskit] Make the context current before disposing it (#36671)

Author: Harry Terkelsen

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

@@ -178,6 +178,9 @@ class Surface {
       // new canvas larger than required to avoid many canvas creations.
       final ui.Size newSize = previousCanvasSize == null ? size : size * 1.4;
 
+      // If we have a surface, send a dummy command to its canvas to make its context
+      // current or else disposing the context could fail below.
+      _surface?.getCanvas().clear(const ui.Color(0x00000000));
       _surface?.dispose();
       _surface = null;
       _addedToScene = false;

lib/web_ui/test/canvaskit/embedded_views_test.dart

@@ -10,6 +10,7 @@ import 'package:ui/src/engine.dart';
 import 'package:ui/ui.dart' as ui;
 
 import 'common.dart';
+import 'test_data.dart';
 
 void main() {
   internalBootstrapBrowserTest(() => testMain);
@@ -618,6 +619,52 @@ void testMain() {
       );
     });
 
+    test('does not crash when resizing the window after textures have been registered', () async {
+      ui.platformViewRegistry.registerViewFactory(
+        'test-platform-view',
+        (int viewId) => createDomHTMLDivElement()..id = 'view-0',
+      );
+      await createPlatformView(0, 'test-platform-view');
+
+      final CkBrowserImageDecoder image = await CkBrowserImageDecoder.create(
+        data: kAnimatedGif,
+        debugSource: 'test',
+      );
+      final ui.FrameInfo frame = await image.getNextFrame();
+      final CkImage ckImage = frame.image as CkImage;
+
+      final LayerSceneBuilder sb = LayerSceneBuilder();
+      sb.pushOffset(0, 0);
+      final CkPictureRecorder recorder = CkPictureRecorder();
+      final CkCanvas canvas = recorder.beginRecording(ui.Rect.largest);
+      canvas.drawImage(ckImage, ui.Offset.zero, CkPaint());
+      final CkPicture picture = recorder.endRecording();
+      sb.addPicture(ui.Offset.zero, picture);
+      sb.addPlatformView(0, width: 10, height: 10);
+
+      window.webOnlyDebugPhysicalSizeOverride = const ui.Size(100, 100);
+      window.debugForceResize();
+      CanvasKitRenderer.instance.rasterizer.draw(sb.build().layerTree);
+      _expectSceneMatches(<_EmbeddedViewMarker>[
+        _overlay,
+        _platformView,
+        _overlay,
+      ]);
+
+      window.webOnlyDebugPhysicalSizeOverride = const ui.Size(200, 200);
+      window.debugForceResize();
+      CanvasKitRenderer.instance.rasterizer.draw(sb.build().layerTree);
+      _expectSceneMatches(<_EmbeddedViewMarker>[
+        _overlay,
+        _platformView,
+        _overlay,
+      ]);
+
+      window.webOnlyDebugPhysicalSizeOverride = null;
+      window.debugForceResize();
+    // ImageDecoder is not supported in Safari or Firefox.
+    }, skip: isSafari || isFirefox);
+
     test('removed the DOM node of an unrendered platform view', () async {
       final Rasterizer rasterizer = CanvasKitRenderer.instance.rasterizer;
       ui.platformViewRegistry.registerViewFactory(