Perform type canonicalization as part of type finalization.

runtime/vm/class_finalizer.h

 // Copyright (c) 2011, 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.
 
 #ifndef VM_CLASS_FINALIZER_H_
 #define VM_CLASS_FINALIZER_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
@@ skipping 45 matching lines @@
   static void FinalizeClass(const Class& cls);
   static bool IsSuperCycleFree(const Class& cls);
   static void CheckForLegalConstClass(const Class& cls);
   static void ResolveSuperClass(const Class& cls);
   static void ResolveDefaultClass(const Class& cls);
   static void ResolveInterfaces(const Class& cls,
                                 GrowableArray<const Class*>* visited);
   static void FinalizeTypeArguments(const Class& cls,
                                     const TypeArguments& arguments);
   static RawType* ResolveType(const Class& cls, const Type& type);
-  static void FinalizeType(const Type& type);
+  static RawType* FinalizeType(const Type& type);
   static void ResolveAndFinalizeSignature(const Class& cls,
                                           const Function& function);
   static void ResolveAndFinalizeMemberTypes(const Class& cls);
   static void PrintClassInformation(const Class& cls);
   static void VerifyClassImplements(const Class& cls);
   static void CollectInterfaces(const Class& cls,
                                 GrowableArray<const Class*>* interfaces);
   static void ReportError(const Script& script,
                           intptr_t token_index,
                           const char* format, ...);
   static void ReportError(const char* format, ...);
 };
 
 }  // namespace dart
 
 #endif  // VM_CLASS_FINALIZER_H_