Minor cleanup.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
@@ skipping 247 matching lines @@
       *peer = data->peer();
       return true;
     }
   }
   return false;
 }
 
 
 void Api::SetWeakHandleReturnValue(NativeArguments* args,
                                    Dart_WeakPersistentHandle retval) {
-  args->SetReturnUnsafe(
-      reinterpret_cast<FinalizablePersistentHandle*>(retval)->raw());
+  args->SetReturnUnsafe(Api::UnwrapAsWeakPersistentHandle(retval)->raw());
 }
 
 
 // --- Handles ---
 
 DART_EXPORT bool Dart_IsError(Dart_Handle handle) {
   return RawObject::IsErrorClassId(Api::ClassId(handle));
 }
 
 
@@ skipping 3956 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 }  // namespace dart