Implement reflecting on mixin applications.

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

Index: dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart b/dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
index 21e7b5ca20fb720a8661c077e3daa58b0f9b5429..28b004109a427defa38fb573111c8817accfcf25 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
@@ -1367,6 +1367,10 @@ class CodeEmitterTask extends CompilerTask {
     Element element = elementOrSelector;
     if (element.isGenerativeConstructorBody()) {
       return null;
+    } else if (element.isClass()) {
+      ClassElement cls = element;
+      if (element.isUnnamedMixinApplication) return null;
+      return cls.name.slowToString();
     }
     throw compiler.internalErrorOnElement(
         element, 'Do not know how to reflect on this $element');
@@ -1977,8 +1981,8 @@ class CodeEmitterTask extends CompilerTask {
     buffer.write('$className:$_');
     buffer.write(jsAst.prettyPrint(builder.toObjectInitializer(), compiler));
     if (backend.shouldRetainName(classElement.name)) {
-      buffer.write(',$n$n"+${classElement.name.slowToString()}": 0');
-      recordedMangledNames.add(className);
+      String reflectionName = getReflectionName(classElement, className);
+      buffer.write(',$n$n"+$reflectionName": 0');
     }
   }