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

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

Index: client/dom/generated/src/frog/WebGLContextAttributes.dart
diff --git a/client/dom/generated/src/frog/WebGLContextAttributes.dart b/client/dom/generated/src/frog/WebGLContextAttributes.dart
index 12bf139f4a64e35f051b4564d8dc4617c4b5cedc..19d2e6586a579eadb2ea7ecfa80c47f97df3996d 100644
--- a/client/dom/generated/src/frog/WebGLContextAttributes.dart
+++ b/client/dom/generated/src/frog/WebGLContextAttributes.dart
@@ -1,27 +1,15 @@
 
 class _WebGLContextAttributesJs extends _DOMTypeJs implements WebGLContextAttributes native "*WebGLContextAttributes" {
 
-  bool get alpha() native "return this.alpha;";
+  bool alpha;
 
-  void set alpha(bool value) native "this.alpha = value;";
+  bool antialias;
 
-  bool get antialias() native "return this.antialias;";
+  bool depth;
 
-  void set antialias(bool value) native "this.antialias = value;";
+  bool premultipliedAlpha;
 
-  bool get depth() native "return this.depth;";
+  bool preserveDrawingBuffer;
 
-  void set depth(bool value) native "this.depth = value;";
-
-  bool get premultipliedAlpha() native "return this.premultipliedAlpha;";
-
-  void set premultipliedAlpha(bool value) native "this.premultipliedAlpha = value;";
-
-  bool get preserveDrawingBuffer() native "return this.preserveDrawingBuffer;";
-
-  void set preserveDrawingBuffer(bool value) native "this.preserveDrawingBuffer = value;";
-
-  bool get stencil() native "return this.stencil;";
-
-  void set stencil(bool value) native "this.stencil = value;";
+  bool stencil;
 }