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

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

 
 class _SVGCursorElementJs extends _SVGElementJs implements SVGCursorElement native "*SVGCursorElement" {
 
-  _SVGAnimatedLengthJs get x() native "return this.x;";
+  final _SVGAnimatedLengthJs x;
 
-  _SVGAnimatedLengthJs get y() native "return this.y;";
+  final _SVGAnimatedLengthJs y;
 
   // From SVGURIReference
 
-  _SVGAnimatedStringJs get href() native "return this.href;";
+  final _SVGAnimatedStringJs href;
 
   // From SVGTests
 
-  _SVGStringListJs get requiredExtensions() native "return this.requiredExtensions;";
+  final _SVGStringListJs requiredExtensions;
 
-  _SVGStringListJs get requiredFeatures() native "return this.requiredFeatures;";
+  final _SVGStringListJs requiredFeatures;
 
-  _SVGStringListJs get systemLanguage() native "return this.systemLanguage;";
+  final _SVGStringListJs systemLanguage;
 
   bool hasExtension(String extension) native;
 
   // From SVGExternalResourcesRequired
 
-  _SVGAnimatedBooleanJs get externalResourcesRequired() native "return this.externalResourcesRequired;";
+  final _SVGAnimatedBooleanJs externalResourcesRequired;
 }