Force slow objects for select objects during startup.

pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart

 // Copyright (c) 2013, 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 dart2js.js_emitter;
 
 // TODO(ahe): Share these with js_helper.dart.
 const FUNCTION_INDEX = 0;
 const NAME_INDEX = 1;
 const CALL_NAME_INDEX = 2;
@@ skipping 37 matching lines @@
       emitter.generateEmbeddedGlobalAccess(embeddedNames.MANGLED_GLOBAL_NAMES);
   jsAst.Expression mangledNamesAccess =
       emitter.generateEmbeddedGlobalAccess(embeddedNames.MANGLED_NAMES);
   jsAst.Expression librariesAccess =
       emitter.generateEmbeddedGlobalAccess(embeddedNames.LIBRARIES);
   jsAst.Expression metadataAccess =
       emitter.generateEmbeddedGlobalAccess(embeddedNames.METADATA);
 
   jsAst.Statement processClassData = js.statement('''{
   function processClassData(cls, descriptor, processedClasses) {
-    var newDesc = {};
+    var newDesc = map(); // Use a slow object.
     var previousProperty;
     var properties = Object.keys(descriptor);
     for (var i = 0; i < properties.length; i++) {
       var property = properties[i];
       var firstChar = property.substring(0, 1);
       if (property === "static") {
         processStatics(#embeddedStatics[cls] = descriptor[property],
                        processedClasses);
       } else if (firstChar === "+") {
         mangledNames[previousProperty] = property.substring(1);
@@ skipping 223 matching lines @@
   if (!#statics) #statics = map();
   if (!#typeInformation) #typeInformation = map(); 
   if (!#globalFunctions) #globalFunctions = map();
   if (#enabledInvokeOn)
     if (!#interceptedNames) #interceptedNames = #interceptedNamesSet;
   var libraries = #libraries;
   var mangledNames = #mangledNames;
   var mangledGlobalNames = #mangledGlobalNames;
   var hasOwnProperty = Object.prototype.hasOwnProperty;
   var length = reflectionData.length;
-  var processedClasses = Object.create(null);
-  processedClasses.collected = Object.create(null);
-  processedClasses.pending = Object.create(null);
+  var processedClasses = map();
+  processedClasses.collected = map();
+  processedClasses.pending = map();
   if (#notInCspMode) {
     processedClasses.constructorsList = [];
     // For every class processed [processedClasses.combinedConstructorFunction]
     // will be updated with the corresponding constructor function. 
     processedClasses.combinedConstructorFunction =
         "function \$reflectable(fn){fn.$reflectableField=1;return fn};\\n"+
         "var \$desc;\\n";
   }
   for (var i = 0; i < length; i++) {
     var data = reflectionData[i];
@@ skipping 169 matching lines @@
 (function() {
   var result = $array[$index];
   if ($check) {
     throw new Error(
         name + ": expected value of type \'$type\' at index " + ($index) +
         " but got " + (typeof result));
   }
   return result;
 })()''';
 }