Make use of __proto__ when available.

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

Index: pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart
index ae053a198240ea4c5c64582a17befe21e4e12937..932d105402d1c6fc2f93b900e39deae9c24e8291 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.dart
@@ -55,24 +55,25 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
 
   jsAst.Statement processClassData = js.statement('''{
   function processClassData(cls, descriptor, processedClasses) {
-    var newDesc = {};
+    descriptor = convertToSlowObject(descriptor); // Use a slow object.
     var previousProperty;
-    for (var property in descriptor) {
-      if (!hasOwnProperty.call(descriptor, property)) continue;
-      var firstChar = property.substring(0, 1);
+    var properties = Object.keys(descriptor);
+    for (var i = 0; i < properties.length; i++) {
+      var property = properties[i];
+      var firstChar = property.charCodeAt(0);
       if (property === "static") {
-        processStatics(#embeddedStatics[cls] = descriptor[property], 
+        processStatics(#embeddedStatics[cls] = descriptor.static,
                        processedClasses);
-      } else if (firstChar === "+") {
+      } else if (firstChar === 43) { // 43 is "+".
         mangledNames[previousProperty] = property.substring(1);
         var flag = descriptor[property];
         if (flag > 0)
           descriptor[previousProperty].$reflectableField = flag;
-      } else if (firstChar === "*") {
-        newDesc[previousProperty].$defaultValuesField = descriptor[property];
-        var optionalMethods = newDesc.$methodsWithOptionalArgumentsField;
+      } else if (firstChar === 42) { // 42 is "*"
+        descriptor[previousProperty].$defaultValuesField = descriptor[property];
+        var optionalMethods = descriptor.$methodsWithOptionalArgumentsField;
         if (!optionalMethods) {
-          newDesc.$methodsWithOptionalArgumentsField = optionalMethods={}
+          descriptor.$methodsWithOptionalArgumentsField = optionalMethods={}
         }
         optionalMethods[property] = previousProperty;
       } else {
@@ -81,9 +82,9 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
             elem != null &&
             elem.constructor === Array &&
             property !== "<>") {
-          addStubs(newDesc, elem, property, false, descriptor, []);
+          addStubs(descriptor, elem, property, false, []);
         } else {
-          newDesc[previousProperty = property] = elem;
+          previousProperty = property;
         }
       }
     }
@@ -94,7 +95,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
      *   'Super;field1,field2'
      * from the CLASS_DESCRIPTOR_PROPERTY property on the descriptor.
      */
-    var classData = newDesc["${namer.classDescriptorProperty}"],
+    var classData = descriptor["${namer.classDescriptorProperty}"],
         split, supr, fields = classData;
 
     if (#hasRetainedMetadata)
@@ -112,7 +113,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
       supr = split[0];
       var functionSignature = split[1];
       if (functionSignature)
-        newDesc.${namer.operatorSignature} = function(s) {
+        descriptor.${namer.operatorSignature} = function(s) {
           return function() {
             return #metadata[s];
           };
@@ -124,7 +125,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
       processedClasses.combinedConstructorFunction += defineClass(cls, fields);
       processedClasses.constructorsList.push(cls);
     }
-    processedClasses.collected[cls] = [globalObject, newDesc];
+    processedClasses.collected[cls] = [globalObject, descriptor];
     classes.push(cls);
   }
 }''', {'embeddedStatics': staticsAccess,
@@ -135,20 +136,21 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
   // TODO(zarah): Remove empty else branches in output when if(#hole) is false.
   jsAst.Statement processStatics = js.statement('''
     function processStatics(descriptor, processedClasses) {
-      for (var property in descriptor) {
-        if (!hasOwnProperty.call(descriptor, property)) continue;
+      var properties = Object.keys(descriptor);
+      for (var i = 0; i < properties.length; i++) {
+        var property = properties[i];
         if (property === "${namer.classDescriptorProperty}") continue;
         var element = descriptor[property];
-        var firstChar = property.substring(0, 1);
+        var firstChar = property.charCodeAt(0);
         var previousProperty;
-        if (firstChar === "+") {
+        if (firstChar === 43) { // 43 is "+".
           mangledGlobalNames[previousProperty] = property.substring(1);
           var flag = descriptor[property];
           if (flag > 0)
             descriptor[previousProperty].$reflectableField = flag;
           if (element && element.length)
             #typeInformation[previousProperty] = element;
-        } else if (firstChar === "*") {
+        } else if (firstChar === 42) { // 42 is "*"
           globalObject[previousProperty].$defaultValuesField = element;
           var optionalMethods = descriptor.$methodsWithOptionalArgumentsField;
           if (!optionalMethods) {
@@ -161,8 +163,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
           #globalFunctions[property] = element;
         } else if (element.constructor === Array) {
           if (#needsStructuredMemberInfo) {
-            addStubs(globalObject, element, property,
-                     true, descriptor, functions);
+            addStubs(globalObject, element, property, true, functions);
           }
         } else {
           // We will not enter this case if no classes are defined.
@@ -184,8 +185,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
    * [array].
    */
   jsAst.Statement addStubs = js.statement('''
-  function addStubs(descriptor, array, name, isStatic,
-                    originalDescriptor, functions) {
+  function addStubs(descriptor, array, name, isStatic, functions) {
     var index = $FUNCTION_INDEX, alias = array[index], f;
     if (typeof alias == "string") {
       f = array[++index];
@@ -193,8 +193,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
       f = alias;
       alias = name;
     }
-    var funcs = [originalDescriptor[name] = descriptor[name] =
-        descriptor[alias] = f];
+    var funcs = [descriptor[name] = descriptor[alias] = f];
     f.\$stubName = name;
     functions.push(name);
     for (; index < array.length; index += 2) {
@@ -203,14 +202,15 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
       f.\$stubName = ${readString("array", "index + 2")};
       funcs.push(f);
       if (f.\$stubName) {
-        originalDescriptor[f.\$stubName] = descriptor[f.\$stubName] = f;
+        descriptor[f.\$stubName] = f;
         functions.push(f.\$stubName);
       }
     }
+    index++;
     for (var i = 0; i < funcs.length; index++, i++) {
-      funcs[i].\$callName = ${readString("array", "index + 1")};
+      funcs[i].\$callName = ${readString("array", "index")};
     }
-    var getterStubName = ${readString("array", "++index")};
+    var getterStubName = ${readString("array", "index")};
     array = array.slice(++index);
     var requiredParameterInfo = ${readInt("array", "0")};
     var requiredParameterCount = requiredParameterInfo >> 1;
@@ -231,7 +231,7 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
       f.\$getterStub = true;
       // Used to create an isolate using spawnFunction.
       if (isStatic) #globalFunctions[name] = f;
-      originalDescriptor[getterStubName] = descriptor[getterStubName] = f;
+      descriptor[getterStubName] = f;
       funcs.push(f);
       if (getterStubName) functions.push(getterStubName);
       f.\$stubName = getterStubName;
@@ -297,9 +297,9 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
   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]
@@ -407,7 +407,8 @@ jsAst.Expression getReflectionDataParser(OldEmitter oldEmitter,
 
     #trivialNsmHandlers;
 
-    for (var cls in processedClasses.pending) finishClass(cls);
+    var properties = Object.keys(processedClasses.pending);
+    for (var i = 0; i < properties.length; i++) finishClass(properties[i]);
   }
 }''', {'allClasses': allClassesAccess,
        'debugFastObjects': DEBUG_FAST_OBJECTS,