Fix issue 2358: dart methods on native classes must also check if the current prototype has the met…

lib/compiler/implementation/ssa/codegen.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   SsaCodeGeneratorTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA code generator';
 
 
   String generateMethod(WorkItem work, HGraph graph) {
     return measure(() {
       compiler.tracer.traceGraph("codegen", graph);
       Map<Element, String> parameterNames = getParameterNames(work);
       String parameters = Strings.join(parameterNames.getValues(), ', ');
       SsaOptimizedCodeGenerator codegen = new SsaOptimizedCodeGenerator(
           compiler, work, parameters, parameterNames);
       codegen.visitGraph(graph);
-      return 'function($parameters) {\n${codegen.buffer}}';
+      
+      FunctionElement element = work.element;
+      String code;
+      if (element.isInstanceMember()
+          && element.enclosingElement.isClass()
+          && element.enclosingElement.isNative()
+          && native.isOverriddenMethod(element,
+                                       element.enclosingElement,
+                                       compiler.emitter.nativeEmitter)) {
+        // Record that this method is overridden. In case of optional
+        // arguments, the emitter will generate stubs to handle them,
+        // and needs to know if the method is overridden.
+        compiler.emitter.nativeEmitter.overriddenMethods.add(element);
+        StringBuffer buffer = new StringBuffer();
+        native.generateMethodWithPrototypeCheckForElement(
+            compiler, buffer, element, '${codegen.buffer}', parameters);
+        code = buffer.toString();
+      } else {
+        code = codegen.buffer.toString();
+      }
+      return 'function($parameters) {\n$code}';
     });
   }
 
   String generateBailoutMethod(WorkItem work, HGraph graph) {
     return measure(() {
       compiler.tracer.traceGraph("codegen-bailout", graph);
       new SsaBailoutPropagator(compiler).visitGraph(graph);
 
       Map<Element, String> parameterNames = getParameterNames(work);
       String parameters = Strings.join(parameterNames.getValues(), ', ');
@@ skipping 1856 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endElse(HIf node) {
     if (node.elseBlock.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }