Add @JSName annotation for native fields and methods.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 713 matching lines @@
                                       bool needsGetter,
                                       bool needsSetter,
                                       bool needsCheckedSetter)) {
     assert(invariant(classElement, classElement.isDeclaration));
     // If the class is never instantiated we still need to set it up for
     // inheritance purposes, but we can simplify its JavaScript constructor.
     bool isInstantiated =
         compiler.codegenWorld.instantiatedClasses.contains(classElement);
 
     void visitField(ClassElement enclosingClass, Element member) {
-      assert(!member.isNative());
       assert(invariant(classElement, member.isDeclaration));
 
       LibraryElement library = member.getLibrary();
       SourceString name = member.name;
       bool isPrivate = name.isPrivate();
       // See if we can dynamically create getters and setters.
       // We can only generate getters and setters for [classElement] since
       // the fields of super classes could be overwritten with getters or
       // setters.
       bool needsGetter = false;
       bool needsSetter = false;
       // We need to name shadowed fields differently, so they don't clash with
       // the non-shadowed field.
       bool isShadowed = false;
       if (identical(enclosingClass, classElement)) {
         needsGetter = instanceFieldNeedsGetter(member);
         needsSetter = instanceFieldNeedsSetter(member);
       } else {
         isShadowed = classElement.isShadowedByField(member);
       }
 
       if ((isInstantiated && !enclosingClass.isNative())
           || needsGetter
           || needsSetter) {
-        String fieldName = isShadowed
+        String accessorName = isShadowed
             ? namer.shadowedFieldName(member)
             : namer.getName(member);
+        String fieldName = member.isNative()
+            ? member.nativeName()
+            : accessorName;
         bool needsCheckedSetter = false;
         if (needsSetter && compiler.enableTypeAssertions
             && canGenerateCheckedSetter(member)) {
           needsCheckedSetter = true;
           needsSetter = false;
         }
         // Getters and setters with suffixes will be generated dynamically.
         addField(member,
                  fieldName,
                  needsGetter,
@@ skipping 474 matching lines @@
    */
   void emitCallStubForGetter(Element member,
                              Set<Selector> selectors,
                              DefineMemberFunction defineInstanceMember) {
     assert(invariant(member, member.isDeclaration));
     LibraryElement memberLibrary = member.getLibrary();
     String getter;
     if (member.isGetter()) {
       getter = "this.${namer.getterName(member.getLibrary(), member.name)}()";
     } else {
-      String name = namer.instanceFieldName(memberLibrary, member.name);
+      String name = member.isNative()
+          ? member.nativeName()
+          : namer.instanceFieldName(memberLibrary, member.name);
       getter = "this.$name";
     }
     for (Selector selector in selectors) {
       if (selector.applies(member, compiler)) {
         String invocationName =
             namer.instanceMethodInvocationName(memberLibrary, member.name,
                                                selector);
         SourceString callName = Namer.CLOSURE_INVOCATION_NAME;
         String closureCallName =
             namer.instanceMethodInvocationName(memberLibrary, callName,
@@ skipping 508 matching lines @@
 const String HOOKS_API_USAGE = """
 // Generated by dart2js, the Dart to JavaScript compiler.
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;