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

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

 
 class _DOMSelectionJs extends _DOMTypeJs implements DOMSelection native "*DOMSelection" {
 
-  _NodeJs get anchorNode() native "return this.anchorNode;";
+  final _NodeJs anchorNode;
 
-  int get anchorOffset() native "return this.anchorOffset;";
+  final int anchorOffset;
 
-  _NodeJs get baseNode() native "return this.baseNode;";
+  final _NodeJs baseNode;
 
-  int get baseOffset() native "return this.baseOffset;";
+  final int baseOffset;
 
-  _NodeJs get extentNode() native "return this.extentNode;";
+  final _NodeJs extentNode;
 
-  int get extentOffset() native "return this.extentOffset;";
+  final int extentOffset;
 
-  _NodeJs get focusNode() native "return this.focusNode;";
+  final _NodeJs focusNode;
 
-  int get focusOffset() native "return this.focusOffset;";
+  final int focusOffset;
 
-  bool get isCollapsed() native "return this.isCollapsed;";
+  final bool isCollapsed;
 
-  int get rangeCount() native "return this.rangeCount;";
+  final int rangeCount;
 
-  String get type() native "return this.type;";
+  final String type;
 
   void addRange(_RangeJs range) native;
 
   void collapse(_NodeJs node, int index) native;
 
   void collapseToEnd() native;
 
   void collapseToStart() native;
 
   bool containsNode(_NodeJs node, bool allowPartial) native;
@@ skipping 11 matching lines @@
   void removeAllRanges() native;
 
   void selectAllChildren(_NodeJs node) native;
 
   void setBaseAndExtent(_NodeJs baseNode, int baseOffset, _NodeJs extentNode, int extentOffset) native;
 
   void setPosition(_NodeJs node, int offset) native;
 
   String toString() native;
 }