Fix implicit access to raw pointer of scoped_refptr.

ipc/ipc_message_attachment_set_posix_unittest.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.
 
 // This test is POSIX only.
 
 #include "ipc/ipc_message_attachment_set.h"
 
 #include <fcntl.h>
 #include <stddef.h>
@@ skipping 136 matching lines @@
   // TODO(morrita): This test is wrong. TakeDescriptorAt() shouldn't be
   // used to retrieve borrowed descriptors. That never happens in production.
   ASSERT_TRUE(
       set->AddAttachment(new internal::PlatformFileAttachment(kFDBase)));
   ASSERT_TRUE(
       set->AddAttachment(new internal::PlatformFileAttachment(kFDBase + 1)));
   ASSERT_TRUE(
       set->AddAttachment(new internal::PlatformFileAttachment(kFDBase + 2)));
 
   ASSERT_EQ(set->GetNonBrokerableAttachmentAt(0)->TakePlatformFile(), kFDBase);
-  ASSERT_EQ(set->GetNonBrokerableAttachmentAt(2), nullptr);
+  ASSERT_FALSE(set->GetNonBrokerableAttachmentAt(2));
 
   set->CommitAllDescriptors();
 }
 
 TEST(MessageAttachmentSet, WalkCycle) {
   scoped_refptr<MessageAttachmentSet> set(new MessageAttachmentSet);
 
   // TODO(morrita): This test is wrong. TakeDescriptorAt() shouldn't be
   // used to retrieve borrowed descriptors. That never happens in production.
   ASSERT_TRUE(
@@ skipping 43 matching lines @@
   const int fd = GetSafeFd();
   ASSERT_TRUE(set->AddAttachment(
       new internal::PlatformFileAttachment(base::ScopedFD(fd))));
   set->CommitAllDescriptors();
 
   ASSERT_TRUE(VerifyClosed(fd));
 }
 
 }  // namespace
 }  // namespace IPC