remove some dead visual studio < 2013 code

base/atomicops_internals_x86_msvc.h

 // Copyright (c) 2006-2008 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 file is an internal atomic implementation, use base/atomicops.h instead.
 
 #ifndef BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
 #define BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
 
 #include <windows.h>
@@ skipping 37 matching lines @@
   return _InterlockedExchangeAdd(
       reinterpret_cast<volatile LONG*>(ptr),
       static_cast<LONG>(increment)) + increment;
 }
 
 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
                                           Atomic32 increment) {
   return Barrier_AtomicIncrement(ptr, increment);
 }
 
-#if !(defined(_MSC_VER) && _MSC_VER >= 1400)
-#error "We require at least vs2005 for MemoryBarrier"
-#endif
 inline void MemoryBarrier() {
 #if defined(ARCH_CPU_64_BITS)
   // See #undef and note at the top of this file.
   __faststorefence();
 #else
   // We use MemoryBarrier from WinNT.h
   ::MemoryBarrier();
 #endif
 }
 
@@ skipping 118 matching lines @@
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 
 #endif  // defined(_WIN64)
 
 }  // namespace base::subtle
 }  // namespace base
 
 #endif  // BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_