Add DartTypes to abstract Types.

pkg/compiler/lib/src/core_types.dart

Index: pkg/compiler/lib/src/core_types.dart
diff --git a/pkg/compiler/lib/src/core_types.dart b/pkg/compiler/lib/src/core_types.dart
index 738cf4118bfaeb8eb1e5b938f90c453b4231d0cf..291978d9e67ef9d8b1608530b922a0f85320e0d8 100644
--- a/pkg/compiler/lib/src/core_types.dart
+++ b/pkg/compiler/lib/src/core_types.dart
@@ -8,6 +8,9 @@ import 'dart_types.dart';
 
 /// The core types in Dart.
 abstract class CoreTypes {
+  /// The `Object` type defined in 'dart:core'.
+  InterfaceType get objectType;
+
   /// The `bool` type defined in 'dart:core'.
   InterfaceType get boolType;
 
@@ -37,4 +40,4 @@ abstract class CoreTypes {
   /// [keyType] and [valueType] as its type arguments.
   InterfaceType mapType([DartType keyType = const DynamicType(),
                          DartType valueType = const DynamicType()]);
-}
+}