Move atomic ops and related files to base library

src/base/atomicops_internals_mac.h

 // Copyright 2010 the V8 project 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 atomicops.h instead.
 
-#ifndef V8_ATOMICOPS_INTERNALS_MAC_H_
-#define V8_ATOMICOPS_INTERNALS_MAC_H_
+#ifndef V8_BASE_ATOMICOPS_INTERNALS_MAC_H_
+#define V8_BASE_ATOMICOPS_INTERNALS_MAC_H_
 
 #include <libkern/OSAtomic.h>
 
 namespace v8 {
-namespace internal {
+namespace base {
 
 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
                                          Atomic32 old_value,
                                          Atomic32 new_value) {
   Atomic32 prev_value;
   do {
     if (OSAtomicCompareAndSwap32(old_value, new_value,
                                  const_cast<Atomic32*>(ptr))) {
       return old_value;
     }
@@ skipping 168 matching lines @@
   return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
 #endif  // defined(__LP64__)
 
-} }  // namespace v8::internal
+} }  // namespace v8::base
 
-#endif  // V8_ATOMICOPS_INTERNALS_MAC_H_
+#endif  // V8_BASE_ATOMICOPS_INTERNALS_MAC_H_