clarify that offset is not used in addPlatformView for iOS/Android

lib/ui/compositing.dart

@@ -715,8 +715,6 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
 
   /// Adds a platform view (e.g an iOS UIView) to the scene.
   ///
-  /// Only supported on iOS, this is currently a no-op on other platforms.
-  ///
   /// On iOS this layer splits the current output surface into two surfaces, one for the scene nodes
   /// preceding the platform view, and one for the scene nodes following the platform view.
   ///
@@ -729,6 +727,8 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   /// With a platform view in the scene, Quartz has to composite the two Flutter surfaces and the
   /// embedded UIView. In addition to that, on iOS versions greater than 9, the Flutter frames are
   /// synchronized with the UIView frames adding additional performance overhead.
+  ///
+  /// The `offset` argument is not used for iOS and Android.
   void addPlatformView(
     int viewId, {
     Offset offset = Offset.zero,

testing/scenario_app/lib/src/platform_view.dart

@@ -707,21 +707,15 @@ mixin _BasePlatformViewScenarioMixin on Scenario {
     SceneBuilder sceneBuilder,
     int viewId,
     double width,
-    double height, {
-    Offset overlayOffset,
-  }) {
-    overlayOffset ??= const Offset(50, 50);
+    double height,
+  ) {
     if (Platform.isIOS) {
-      sceneBuilder.addPlatformView(viewId, offset: overlayOffset, width: width, height: height);
+      sceneBuilder.addPlatformView(viewId, width: width, height: height);
     } else if (Platform.isAndroid) {
       if (usesAndroidHybridComposition) {
-        // Hybrid composition does not support `offset`.
-        // https://github.com/flutter/flutter/issues/60630
-        sceneBuilder.pushOffset(overlayOffset.dx, overlayOffset.dy);
         sceneBuilder.addPlatformView(viewId, width: width, height: height);
-        sceneBuilder.pop();
       } else if (_textureId != null) {
-        sceneBuilder.addTexture(_textureId, offset: overlayOffset, width: width, height: height);
+        sceneBuilder.addTexture(_textureId, width: width, height: height);
       }
     } else {
       throw UnsupportedError('Platform ${Platform.operatingSystem} is not supported');
@@ -740,7 +734,6 @@ mixin _BasePlatformViewScenarioMixin on Scenario {
       viewId,
       500,
       500,
-      overlayOffset: overlayOffset,
     );
     final PictureRecorder recorder = PictureRecorder();
     final Canvas canvas = Canvas(recorder);