Reapply "Add TypeVariable object on runtime to support reflection on type variables." and …

sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.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;
 
 class ClassEmitter extends CodeEmitterHelper {
   /**
    * Documentation wanted -- johnniwinther
    *
@@ skipping 279 matching lines @@
                                           ClassElement classElement,
                                           ClassBuilder builder,
                                           CodeBuffer buffer) {
     var metadata = task.metadataEmitter.buildMetadataFunction(classElement);
     if (metadata != null) {
       builder.addProperty("@", metadata);
     }
 
     if (backend.isNeededForReflection(classElement)) {
       Link typeVars = classElement.typeVariables;
-      List properties = [];
-      for (TypeVariableType typeVar in typeVars) {
-        properties.add(js.string(typeVar.name.slowToString()));
-        properties.add(
-            js.toExpression(
-                task.metadataEmitter.reifyType(typeVar.element.bound)));
+      Iterable properties = [];
+      if (task.typeVariableHandler.typeVariablesOf(classElement) != null) {
+        properties = task.typeVariableHandler.typeVariablesOf(classElement)
+            .map(js.toExpression);
       }
 
       ClassElement superclass = classElement.superclass;
       bool hasSuper = superclass != null;
       if ((!properties.isEmpty && !hasSuper) ||
           (hasSuper && superclass.typeVariables != typeVars)) {
         builder.addProperty('<>', new jsAst.ArrayInitializer.from(properties));
       }
     }
     List<CodeBuffer> classBuffers = task.elementBuffers[classElement];
@@ skipping 26 matching lines @@
     }
 
     // TODO(ahe): This method (generateClass) should return a jsAst.Expression.
     if (!buffer.isEmpty) {
       buffer.write(',$n$n');
     }
     buffer.write('$className:$_');
     buffer.write(jsAst.prettyPrint(builder.toObjectInitializer(), compiler));
     String reflectionName = task.getReflectionName(classElement, className);
     if (reflectionName != null) {
-      List<int> interfaces = <int>[];
-      for (DartType interface in classElement.interfaces) {
-        interfaces.add(task.metadataEmitter.reifyType(interface));
+      if (!backend.isNeededForReflection(classElement)) {
+        buffer.write(',$n$n"+$reflectionName": 0');
+      } else {
+        List<int> interfaces = <int>[];
+        for (DartType interface in classElement.interfaces) {
+          interfaces.add(task.metadataEmitter.reifyType(interface));
+        }
+        buffer.write(',$n$n"+$reflectionName": $interfaces');
       }
-      buffer.write(',$n$n"+$reflectionName": $interfaces');
     }
   }
 
   /**
    * Calls [addField] for each of the fields of [element].
    *
    * [element] must be a [ClassElement] or a [LibraryElement].
    *
    * If [element] is a [ClassElement], the static fields of the class are
    * visited if [visitStatics] is true and the instance fields are visited if
@@ skipping 226 matching lines @@
         ? new Selector.getter(member.name, member.getLibrary())
         : new Selector.setter(member.name, member.getLibrary());
     String reflectionName = task.getReflectionName(selector, name);
     if (reflectionName != null) {
       var reflectable =
           js(backend.isAccessibleByReflection(member) ? '1' : '0');
       builder.addProperty('+$reflectionName', reflectable);
     }
   }
 }