Get rid of a lot of () for getters.

lib/html/src/ErrorEventWrappingImplementation.dart

Index: lib/html/src/ErrorEventWrappingImplementation.dart
diff --git a/lib/html/src/ErrorEventWrappingImplementation.dart b/lib/html/src/ErrorEventWrappingImplementation.dart
index 2843306d849b6f98fcab9bbe8b308d0f2fd7ca07..44a821434939147be8c37e2f889eb78236127e48 100644
--- a/lib/html/src/ErrorEventWrappingImplementation.dart
+++ b/lib/html/src/ErrorEventWrappingImplementation.dart
@@ -13,9 +13,9 @@ class ErrorEventWrappingImplementation extends EventWrappingImplementation imple
     return LevelDom.wrapErrorEvent(e);
   }
 
-  String get filename() => _ptr.filename;
+  String get filename => _ptr.filename;
 
-  int get lineno() => _ptr.lineno;
+  int get lineno => _ptr.lineno;
 
-  String get message() => _ptr.message;
+  String get message => _ptr.message;
 }