Make fill parameter in context2d default to 'nonzero' as per the spec.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index e44393d955881ba0283cf9aacbb804c567df5c75..48e743efca3aa3fa62874594b46c07d08d455b8e 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -1605,10 +1605,6 @@ class CanvasRenderingContext2D extends CanvasRenderingContext native "CanvasRend
   @Experimental() // untriaged
   void ellipse(num x, num y, num radiusX, num radiusY, num rotation, num startAngle, num endAngle, bool anticlockwise) native;
 
-  @DomName('CanvasRenderingContext2D.fill')
-  @DocsEditable()
-  void fill([String winding]) native;
-
   @DomName('CanvasRenderingContext2D.fillRect')
   @DocsEditable()
   void fillRect(num x, num y, num width, num height) native;
@@ -2062,6 +2058,11 @@ class CanvasRenderingContext2D extends CanvasRenderingContext native "CanvasRend
       JS('void', '#.fillText(#, #, #)', this, text, x, y);
     }
   }
+
+  @DomName('CanvasRenderingContext2D.fill')
+  void fill([String winding = 'nonzero']) {
+    JS('void', '#.fill(#)', this, winding);
+  }
 }
 
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file