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

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

 
 class _SVGLineElementJs extends _SVGElementJs implements SVGLineElement native "*SVGLineElement" {
 
-  _SVGAnimatedLengthJs get x1() native "return this.x1;";
+  final _SVGAnimatedLengthJs x1;
 
-  _SVGAnimatedLengthJs get x2() native "return this.x2;";
+  final _SVGAnimatedLengthJs x2;
 
-  _SVGAnimatedLengthJs get y1() native "return this.y1;";
+  final _SVGAnimatedLengthJs y1;
 
-  _SVGAnimatedLengthJs get y2() native "return this.y2;";
+  final _SVGAnimatedLengthJs y2;
 
   // 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 SVGLangSpace
 
-  String get xmllang() native "return this.xmllang;";
+  String xmllang;
 
-  void set xmllang(String value) native "this.xmllang = value;";
-
-  String get xmlspace() native "return this.xmlspace;";
-
-  void set xmlspace(String value) native "this.xmlspace = value;";
+  String xmlspace;
 
   // From SVGExternalResourcesRequired
 
-  _SVGAnimatedBooleanJs get externalResourcesRequired() native "return this.externalResourcesRequired;";
+  final _SVGAnimatedBooleanJs externalResourcesRequired;
 
   // From SVGStylable
 
-  _SVGAnimatedStringJs get className() native "return this.className;";
+  final _SVGAnimatedStringJs className;
 
-  _CSSStyleDeclarationJs get style() native "return this.style;";
+  final _CSSStyleDeclarationJs style;
 
   _CSSValueJs getPresentationAttribute(String name) native;
 
   // From SVGTransformable
 
-  _SVGAnimatedTransformListJs get transform() native "return this.transform;";
+  final _SVGAnimatedTransformListJs transform;
 
   // From SVGLocatable
 
-  _SVGElementJs get farthestViewportElement() native "return this.farthestViewportElement;";
+  final _SVGElementJs farthestViewportElement;
 
-  _SVGElementJs get nearestViewportElement() native "return this.nearestViewportElement;";
+  final _SVGElementJs nearestViewportElement;
 
   _SVGRectJs getBBox() native;
 
   _SVGMatrixJs getCTM() native;
 
   _SVGMatrixJs getScreenCTM() native;
 
   _SVGMatrixJs getTransformToElement(_SVGElementJs element) native;
 }