[web] Support flutterViewId in platform view messages

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

@@ -21,6 +21,9 @@ ui.VoidCallback? scheduleFrameCallback;
 typedef HighContrastListener = void Function(bool enabled);
 typedef _KeyDataResponseCallback = void Function(bool handled);
 
+const StandardMethodCodec standardCodec = StandardMethodCodec();
+const JSONMethodCodec jsonCodec = JSONMethodCodec();
+
 /// Determines if high contrast is enabled using media query 'forced-colors: active' for Windows
 class HighContrastSupport {
   static HighContrastSupport instance = HighContrastSupport();
@@ -129,13 +132,13 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
 
   /// The current list of windows.
   @override
-  Iterable<ui.FlutterView> get views => viewData.values;
-  final Map<int, ui.FlutterView> viewData = <int, ui.FlutterView>{};
+  Iterable<EngineFlutterView> get views => viewData.values;
+  final Map<int, EngineFlutterView> viewData = <int, EngineFlutterView>{};
 
   /// Returns the [FlutterView] with the provided ID if one exists, or null
   /// otherwise.
   @override
-  ui.FlutterView? view({required int id}) => viewData[id];
+  EngineFlutterView? view({required int id}) => viewData[id];
 
   /// A map of opaque platform window identifiers to window configurations.
   ///
@@ -470,8 +473,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
 
       /// This should be in sync with shell/common/shell.cc
       case 'flutter/skia':
-        const MethodCodec codec = JSONMethodCodec();
-        final MethodCall decoded = codec.decodeMethodCall(data);
+        final MethodCall decoded = jsonCodec.decodeMethodCall(data);
         switch (decoded.method) {
           case 'Skia.setResourceCacheMaxBytes':
             if (renderer is CanvasKitRenderer) {
@@ -486,7 +488,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
             // Also respond in HTML mode. Otherwise, apps would have to detect
             // CanvasKit vs HTML before invoking this method.
             replyToPlatformMessage(
-                callback, codec.encodeSuccessEnvelope(<bool>[true]));
+                callback, jsonCodec.encodeSuccessEnvelope(<bool>[true]));
         }
         return;
 
@@ -496,22 +498,21 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
         return;
 
       case 'flutter/platform':
-        const MethodCodec codec = JSONMethodCodec();
-        final MethodCall decoded = codec.decodeMethodCall(data);
+        final MethodCall decoded = jsonCodec.decodeMethodCall(data);
         switch (decoded.method) {
           case 'SystemNavigator.pop':
             // TODO(a-wallen): As multi-window support expands, the pop call
             // will need to include the view ID. Right now only one view is
             // supported.
             implicitView!.browserHistory.exit().then((_) {
               replyToPlatformMessage(
-                  callback, codec.encodeSuccessEnvelope(true));
+                  callback, jsonCodec.encodeSuccessEnvelope(true));
             });
             return;
           case 'HapticFeedback.vibrate':
             final String? type = decoded.arguments as String?;
             vibrate(_getHapticFeedbackDuration(type));
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
           case 'SystemChrome.setApplicationSwitcherDescription':
             final Map<String, Object?> arguments = decoded.arguments as Map<String, Object?>;
@@ -520,24 +521,24 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
             final int primaryColor = arguments['primaryColor'] as int? ?? 0xFF000000;
             domDocument.title = label;
             setThemeColor(ui.Color(primaryColor));
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
           case 'SystemChrome.setSystemUIOverlayStyle':
             final Map<String, Object?> arguments = decoded.arguments as Map<String, Object?>;
             final int? statusBarColor = arguments['statusBarColor'] as int?;
             setThemeColor(statusBarColor == null ? null : ui.Color(statusBarColor));
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
           case 'SystemChrome.setPreferredOrientations':
             final List<dynamic> arguments = decoded.arguments as List<dynamic>;
             ScreenOrientation.instance.setPreferredOrientation(arguments).then((bool success) {
               replyToPlatformMessage(
-                  callback, codec.encodeSuccessEnvelope(success));
+                  callback, jsonCodec.encodeSuccessEnvelope(success));
             });
             return;
           case 'SystemSound.play':
             // There are no default system sounds on web.
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
           case 'Clipboard.setData':
             ClipboardMessageHandler().setDataMethodCall(decoded, callback);
@@ -560,23 +561,21 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
         return;
 
       case 'flutter/contextmenu':
-        const MethodCodec codec = JSONMethodCodec();
-        final MethodCall decoded = codec.decodeMethodCall(data);
+        final MethodCall decoded = jsonCodec.decodeMethodCall(data);
         switch (decoded.method) {
           case 'enableContextMenu':
             implicitView!.contextMenu.enable();
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
           case 'disableContextMenu':
             implicitView!.contextMenu.disable();
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
             return;
         }
         return;
 
       case 'flutter/mousecursor':
-        const MethodCodec codec = StandardMethodCodec();
-        final MethodCall decoded = codec.decodeMethodCall(data);
+        final MethodCall decoded = standardCodec.decodeMethodCall(data);
         final Map<dynamic, dynamic> arguments = decoded.arguments as Map<dynamic, dynamic>;
         switch (decoded.method) {
           case 'activateSystemCursor':
@@ -585,15 +584,21 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
         return;
 
       case 'flutter/web_test_e2e':
-        const MethodCodec codec = JSONMethodCodec();
         replyToPlatformMessage(
             callback,
-            codec.encodeSuccessEnvelope(
-                _handleWebTestEnd2EndMessage(codec, data)));
+            jsonCodec.encodeSuccessEnvelope(
+                _handleWebTestEnd2EndMessage(jsonCodec, data)));
         return;
 
       case 'flutter/platform_views':
-        implicitView!.platformViewMessageHandler.handlePlatformViewCall(data, callback!);
+        final MethodCall(:String method, :dynamic arguments) = standardCodec.decodeMethodCall(data);
+        final int? flutterViewId = tryFlutterViewId(arguments);
+        if (flutterViewId == null) {
+          implicitView!.platformViewMessageHandler.handleLegacyPlatformViewCall(method, arguments, callback!);
+          return;
+        }
+        arguments as Map<dynamic, dynamic>;
+        viewData[flutterViewId]!.platformViewMessageHandler.handlePlatformViewCall(method, arguments, callback!);
         return;
 
       case 'flutter/accessibility':
@@ -609,8 +614,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
         // supported.
         implicitView!.handleNavigationMessage(data).then((bool handled) {
           if (handled) {
-            const MethodCodec codec = JSONMethodCodec();
-            replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+            replyToPlatformMessage(callback, jsonCodec.encodeSuccessEnvelope(true));
           } else {
             callback?.call(null);
           }
@@ -1350,7 +1354,7 @@ class ViewConfiguration {
   });
 
   ViewConfiguration copyWith({
-    ui.FlutterView? view,
+    EngineFlutterView? view,
     double? devicePixelRatio,
     ui.Rect? geometry,
     bool? visible,
@@ -1375,7 +1379,7 @@ class ViewConfiguration {
     );
   }
 
-  final ui.FlutterView? view;
+  final EngineFlutterView? view;
   final double devicePixelRatio;
   final ui.Rect geometry;
   final bool visible;

lib/web_ui/lib/src/engine/platform_views/content_manager.dart

@@ -249,5 +249,9 @@ DomElement _defaultFactory(
 }) {
   params!;
   params as Map<Object?, Object?>;
-  return domDocument.createElement(params.readString('tagName'));
+  final DomElement element = domDocument.createElement(params.readString('tagName'));
+  element.style
+    ..width = '100%'
+    ..height = '100%';
+  return element;
 }

lib/web_ui/lib/src/engine/platform_views/message_handler.dart

@@ -63,13 +63,12 @@ class PlatformViewMessageHandler {
   /// If all goes well, this function will `callback` with an empty success envelope.
   /// In case of error, this will `callback` with an error envelope describing the error.
   void _createPlatformView(
-    MethodCall methodCall,
+    Map<dynamic, dynamic> arguments,
     _PlatformMessageResponseCallback callback,
   ) {
-    final Map<dynamic, dynamic> args = methodCall.arguments as Map<dynamic, dynamic>;
-    final int viewId = args.readInt('id');
-    final String viewType = args.readString('viewType');
-    final Object? params = args['params'];
+    final int viewId = arguments.readInt('id');
+    final String viewType = arguments.readString('viewType');
+    final Object? params = arguments['params'];
 
     if (!_contentManager.knowsViewType(viewType)) {
       callback(_codec.encodeErrorEnvelope(
@@ -114,34 +113,53 @@ class PlatformViewMessageHandler {
   ///
   /// This function should always `callback` with an empty success envelope.
   void _disposePlatformView(
-    MethodCall methodCall,
+    int viewId,
     _PlatformMessageResponseCallback callback,
   ) {
-    final int viewId = methodCall.arguments as int;
-
     // The contentManager removes the slot and the contents from its internal
     // cache, and the DOM.
     _contentManager.clearPlatformView(viewId);
 
     callback(_codec.encodeSuccessEnvelope(null));
   }
 
+  /// Handles legacy PlatformViewCalls that don't contain a `flutterViewId`.
+  ///
+  /// This is transitional code to support the old platform view channel. As
+  /// soon as the framework code is updated to send the `flutterViewId`, this
+  /// method can be removed.
+  void handleLegacyPlatformViewCall(
+    String method,
+    dynamic arguments,
+    _PlatformMessageResponseCallback callback,
+  ) {
+    switch (method) {
+      case 'create':
+        _createPlatformView(arguments as Map<dynamic, dynamic>, callback);
+        return;
+      case 'dispose':
+        _disposePlatformView(arguments as int, callback);
+        return;
+    }
+    callback(null);
+  }
+
   /// Handles a PlatformViewCall to the `flutter/platform_views` channel.
   ///
   /// This method handles two possible messages:
   /// * `create`: See [_createPlatformView]
   /// * `dispose`: See [_disposePlatformView]
   void handlePlatformViewCall(
-    ByteData? data,
+    String method,
+    Map<dynamic, dynamic> arguments,
     _PlatformMessageResponseCallback callback,
   ) {
-    final MethodCall decoded = _codec.decodeMethodCall(data);
-    switch (decoded.method) {
+    switch (method) {
       case 'create':
-        _createPlatformView(decoded, callback);
+        _createPlatformView(arguments, callback);
         return;
       case 'dispose':
-        _disposePlatformView(decoded, callback);
+        _disposePlatformView(arguments.readInt('id'), callback);
         return;
     }
     callback(null);

lib/web_ui/lib/src/engine/util.dart

@@ -14,6 +14,7 @@ import 'package:ui/ui.dart' as ui;
 import 'browser_detection.dart';
 import 'dom.dart';
 import 'safe_browser_api.dart';
+import 'services.dart';
 import 'vector_math.dart';
 
 /// Generic callback signature, used by [_futurize].
@@ -627,6 +628,23 @@ extension JsonExtensions on Map<dynamic, dynamic> {
   }
 }
 
+/// Extracts view ID from the [MethodCall.arguments] map.
+///
+/// Throws if the view ID is not present or if [arguments] is not a map.
+int readFlutterViewId(Object? arguments) {
+  return tryFlutterViewId(arguments)!;
+}
+
+/// Extracts view ID from the [MethodCall.arguments] map.
+///
+/// Returns null if the view ID is not present or if [arguments] is not a map.
+int? tryFlutterViewId(Object? arguments) {
+  if (arguments is Map) {
+    return arguments.tryInt('flutterViewId');
+  }
+  return null;
+}
+
 /// Prints a list of bytes in hex format.
 ///
 /// Bytes are separated by one space and are padded on the left to always show