Minor build fixes for aura/touchui

ui/base/dragdrop/os_exchange_data_provider_aura.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/base/dragdrop/os_exchange_data.h"
 
 #include "base/logging.h"
 
 namespace ui {
 
@@ skipping 51 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 // OSExchangeData, public:
 
 // static
 OSExchangeData::Provider* OSExchangeData::CreateProvider() {
   return new OSExchangeDataProviderAura();
 }
 
 // static
-void* OSExchangeData::RegisterCustomFormat(const std::string& type) {
+OSExchangeData::CustomFormat
+OSExchangeData::RegisterCustomFormat(const std::string& type) {
   // TODO(davemoore) Implement this for aura.
   return NULL;
 }
 
 }  // namespace ui