Convert verification of options structs to use the new user pointer handling (see r285350).

mojo/system/dispatcher_unittest.cc

 // Copyright 2013 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 "mojo/system/dispatcher.h"
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 177 matching lines @@
                                              NullUserPointer(),
                                              MOJO_READ_DATA_FLAG_NONE));
         break;
       case END_READ_DATA:
         EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
                   dispatcher_->EndReadData(0));
         break;
       case DUPLICATE_BUFFER_HANDLE: {
         scoped_refptr<Dispatcher> unused;
         EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
-                  dispatcher_->DuplicateBufferHandle(NULL, &unused));
+                  dispatcher_->DuplicateBufferHandle(NullUserPointer(),
+                                                     &unused));
         break;
       }
       case MAP_BUFFER: {
         scoped_ptr<RawSharedBufferMapping> unused;
         EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
                   dispatcher_->MapBuffer(0u, 0u, MOJO_MAP_BUFFER_FLAG_NONE,
                                          &unused));
         break;
       }
       case ADD_WAITER: {
@@ skipping 71 matching lines @@
       event.Signal();  // Kicks off real work on the threads.
     }  // Joins all the threads.
 
     EXPECT_EQ(MOJO_RESULT_OK, d->Close());
   }
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo