Hoist generics-related functions from ClassMirror to TypeMirror.

runtime/lib/mirrors_impl.dart

 // Copyright (c) 2012, 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.
 
 // VM-specific implementation of the dart:mirrors library.
 
 import "dart:collection";
 
 final emptyList = new UnmodifiableListView([]);
 final emptyMap = new _UnmodifiableMapView({});
@@ skipping 1397 matching lines @@
 }
 
 class _SpecialTypeMirrorImpl extends _LocalMirrorImpl
     implements TypeMirror, DeclarationMirror {
   _SpecialTypeMirrorImpl(String name) : simpleName = _s(name);
 
   final bool isPrivate = false;
   final DeclarationMirror owner = null;
   final Symbol simpleName;
   final bool isTopLevel = true;
-  // Fixed length 0, therefore immutable.
   final List<InstanceMirror> metadata = emptyList;
 
+  List<TypeVariableMirror> get typeVariables => emptyList;
+  List<TypeMirror> get typeArguments => emptyList;
+
+  bool get isOriginalDeclaration => true;
+  TypeMirror get originalDeclaration => this;
+
   SourceLocation get location {
     throw new UnimplementedError('TypeMirror.location is not implemented');
   }
 
   Symbol get qualifiedName => simpleName;
 
   // TODO(11955): Remove once dynamicType and voidType are canonical objects in
   // the object store.
   bool operator ==(other) {
     if (other is! _SpecialTypeMirrorImpl) {
@@ skipping 74 matching lines @@
     if (typeMirror == null) {
       typeMirror = makeLocalTypeMirror(key);
       _instanitationCache[key] = typeMirror;
       if (typeMirror is ClassMirror && !typeMirror._isGeneric) {
         _declarationCache[key] = typeMirror;
       }
     }
     return typeMirror;
   }
 }