add support for native methods in class

pkg/compiler/lib/src/parser/element_listener.dart

Index: pkg/compiler/lib/src/parser/element_listener.dart
diff --git a/pkg/compiler/lib/src/parser/element_listener.dart b/pkg/compiler/lib/src/parser/element_listener.dart
index 1f1843385a178193a54083ab9ccee91713e06032..82f39a9e931f1bbbcaddc73d7e93569365fccd89 100644
--- a/pkg/compiler/lib/src/parser/element_listener.dart
+++ b/pkg/compiler/lib/src/parser/element_listener.dart
@@ -527,6 +527,7 @@ class ElementListener extends Listener {
 
   @override
   void handleRecoverableError(Token token, Message message) {
+    if (message == codes.messageNativeClauseShouldBeAnnotation) return;
     handleError(token, message);
   }
 
@@ -552,7 +553,7 @@ class ElementListener extends Listener {
     switch (message.code.dart2jsCode) {
       case "MISSING_TOKEN_BEFORE_THIS":
         String expected = arguments["string"];
-        // TODO(danrubel) This functionality is being replaced by
+        // TODO(danrubel): This functionality is being replaced by
         // the parser's ensureSemicolon method.
         if (identical(";", expected)) {
           // When a semicolon is missing, it often leads to an error on the