make base::SharedMemoryHandle a class on POSIX.

base/metrics/field_trial.cc

 // Copyright (c) 2012 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 "base/metrics/field_trial.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/base_switches.h"
@@ skipping 1138 matching lines @@
   if (!kUseSharedMemoryForFieldTrials)
     return false;
 
   if (fd_key == -1)
     return false;
 
   int fd = GlobalDescriptors::GetInstance()->MaybeGet(fd_key);
   if (fd == -1)
     return false;
 
-#if defined(OS_MACOSX) && !defined(OS_IOS)
   SharedMemoryHandle shm_handle(FileDescriptor(fd, true));
-#else
-  SharedMemoryHandle shm_handle(fd, true);
-#endif
 
   bool result = FieldTrialList::CreateTrialsFromSharedMemoryHandle(shm_handle);
   DCHECK(result);
   return true;
 }
 #endif
 
 // static
 bool FieldTrialList::CreateTrialsFromSharedMemoryHandle(
     SharedMemoryHandle shm_handle) {
@@ skipping 184 matching lines @@
     return;
   }
   AutoLock auto_lock(global_->lock_);
   CHECK(!global_->PreLockedFind(trial->trial_name())) << trial->trial_name();
   trial->AddRef();
   trial->SetTrialRegistered();
   global_->registered_[trial->trial_name()] = trial;
 }
 
 }  // namespace base