Use fields in hidden native DOM classes instead of getters/setters.

client/dom/generated/src/frog/SVGViewSpec.dart

Index: client/dom/generated/src/frog/SVGViewSpec.dart
diff --git a/client/dom/generated/src/frog/SVGViewSpec.dart b/client/dom/generated/src/frog/SVGViewSpec.dart
index d3122692170ec3a819806f1dd9a61f796c72b5c4..08ebccebf844323226714287087ea6b0f3515779 100644
--- a/client/dom/generated/src/frog/SVGViewSpec.dart
+++ b/client/dom/generated/src/frog/SVGViewSpec.dart
@@ -1,21 +1,21 @@
 
 class _SVGViewSpecJs extends _SVGZoomAndPanJs implements SVGViewSpec native "*SVGViewSpec" {
 
-  String get preserveAspectRatioString() native "return this.preserveAspectRatioString;";
+  final String preserveAspectRatioString;
 
-  _SVGTransformListJs get transform() native "return this.transform;";
+  final _SVGTransformListJs transform;
 
-  String get transformString() native "return this.transformString;";
+  final String transformString;
 
-  String get viewBoxString() native "return this.viewBoxString;";
+  final String viewBoxString;
 
-  _SVGElementJs get viewTarget() native "return this.viewTarget;";
+  final _SVGElementJs viewTarget;
 
-  String get viewTargetString() native "return this.viewTargetString;";
+  final String viewTargetString;
 
   // From SVGFitToViewBox
 
-  _SVGAnimatedPreserveAspectRatioJs get preserveAspectRatio() native "return this.preserveAspectRatio;";
+  final _SVGAnimatedPreserveAspectRatioJs preserveAspectRatio;
 
-  _SVGAnimatedRectJs get viewBox() native "return this.viewBox;";
+  final _SVGAnimatedRectJs viewBox;
 }