Add @JSName annotation for native fields and methods.

sdk/lib/_internal/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.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
 
@@ skipping 1704 matching lines @@
 
   visitFieldGet(HFieldGet node) {
     use(node.receiver);
     if (node.element == backend.jsArrayLength
         || node.element == backend.jsStringLength) {
       // We're accessing a native JavaScript property called 'length'
       // on a JS String or a JS array. Therefore, the name of that
       // property should not be mangled.
       push(new js.PropertyAccess.field(pop(), 'length'), node);
     } else {
-      String name = backend.namer.getName(node.element);
+      String name = _fieldPropertyName(node.element);
       push(new js.PropertyAccess.field(pop(), name), node);
       HType receiverHType = types[node.receiver];
       DartType type = receiverHType.computeType(compiler);
       if (type != null) {
         world.registerFieldGetter(
             node.element.name, node.element.getLibrary(), type);
       }
     }
   }
 
   visitFieldSet(HFieldSet node) {
-    String name = backend.namer.getName(node.element);
+    String name = _fieldPropertyName(node.element);
     DartType type = types[node.receiver].computeType(compiler);
     if (type != null) {
       // Field setters in the generative constructor body are handled in a
       // step "SsaConstructionFieldTypes" in the ssa optimizer.
       if (!work.element.isGenerativeConstructorBody()) {
         world.registerFieldSetter(
             node.element.name, node.element.getLibrary(), type);
         backend.registerFieldSetter(
             work.element, node.element, types[node.value]);
       }
     }
     use(node.receiver);
     js.Expression receiver = pop();
     use(node.value);
     push(new js.Assignment(new js.PropertyAccess.field(receiver, name), pop()),
-         node);
+        node);
   }
 
+  String _fieldPropertyName(Element element) => element.isNative()
+      ? element.nativeName()
+      : backend.namer.getName(element);
+
   visitLocalGet(HLocalGet node) {
     use(node.receiver);
   }
 
   visitLocalSet(HLocalSet node) {
     use(node.value);
     assignVariable(variableNames.getName(node.receiver), pop());
   }
 
   visitForeign(HForeign node) {
@@ skipping 1254 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }