Implement ObjectMirror.[]

sdk/lib/_internal/lib/js_mirrors.dart

Index: sdk/lib/_internal/lib/js_mirrors.dart
diff --git a/sdk/lib/_internal/lib/js_mirrors.dart b/sdk/lib/_internal/lib/js_mirrors.dart
index 4d0fe517fc221b9a484387446e254ede35b54dcb..3832c89d2bbb2d27d76c5c5c4c2965e0f7a16f1a 100644
--- a/sdk/lib/_internal/lib/js_mirrors.dart
+++ b/sdk/lib/_internal/lib/js_mirrors.dart
@@ -421,6 +421,8 @@ class JsLibraryMirror extends JsDeclarationMirror with JsObjectMirror
 
   // TODO(ahe): Test this getter.
   DeclarationMirror get owner => null;
+
+  Function operator [](Symbol selector) => throw new UnimplementedError();
 }
 
 String n(Symbol symbol) => _symbol_dev.Symbol.getName(symbol);
@@ -775,6 +777,8 @@ class JsInstanceMirror extends JsObjectMirror implements InstanceMirror {
     return JSInvocationMirror.invokeFromMirror(invocation, reflectee);
   }
 
+  Function operator [](Symbol selector) => throw new UnimplementedError();
+
   operator ==(other) {
     return other is JsInstanceMirror &&
            identical(reflectee, other.reflectee);
@@ -1323,6 +1327,8 @@ class JsClassMirror extends JsTypeMirror with JsObjectMirror
   }
 
   List<TypeMirror> get typeArguments => new List();
+
+  Function operator [](Symbol selector) => throw new UnimplementedError();
 }
 
 class JsVariableMirror extends JsDeclarationMirror implements VariableMirror {