Reapply "Avoid use of empty string as a property name."

sdk/lib/_internal/compiler/implementation/js_backend/namer.dart

 // Copyright (c) 2011, 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;
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class Namer implements ClosureNamer {
@@ skipping 209 matching lines @@
   final String currentIsolate = r'$';
   final String getterPrefix = r'get$';
   final String setterPrefix = r'set$';
   final String metadataField = '@';
   final String callCatchAllName = r'call$catchAll';
   final String reflectableField = r'$reflectable';
   final String defaultValuesField = r'$defaultValues';
   final String methodsWithOptionalArgumentsField =
       r'$methodsWithOptionalArguments';
 
+  final String classDescriptorProperty = r'^';
+
   // Name of property in a class description for the native dispatch metadata.
   final String nativeSpecProperty = '%';
 
   static final RegExp IDENTIFIER = new RegExp(r'^[A-Za-z_$][A-Za-z0-9_$]*$');
   static final RegExp NON_IDENTIFIER_CHAR = new RegExp(r'[^A-Za-z_0-9$]');
 
   /**
    * Map from top-level or static elements to their unique identifiers provided
    * by [getName].
    *
@@ skipping 43 matching lines @@
   String get STATIC_CLOSURE_NAME_NAME => r'$name';
   String get closureInvocationSelectorName => Compiler.CALL_OPERATOR_NAME;
   bool get shouldMinify => false;
 
   String getNameForJsGetName(Node node, String name) {
     switch (name) {
       case 'GETTER_PREFIX': return getterPrefix;
       case 'SETTER_PREFIX': return setterPrefix;
       case 'CALL_CATCH_ALL': return callCatchAllName;
       case 'REFLECTABLE': return reflectableField;
+      case 'CLASS_DESCRIPTOR_PROPERTY': return classDescriptorProperty;
       default:
         compiler.reportError(
             node, MessageKind.GENERIC,
             {'text': 'Error: Namer has no name for "$name".'});
         return 'BROKEN';
     }
   }
 
   String constantName(Constant constant) {
     // In the current implementation it doesn't make sense to give names to
@@ skipping 1092 matching lines @@
         if (!first) {
           sb.write('_');
         }
         sb.write('_');
         visit(link.head);
         first = true;
       }
     }
   }
 }