base: Add/Fix namespace closing comments.

base/atomicops_internals_arm64_gcc.h

 // Copyright 2014 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.
 
 // TODO(rmcilroy): Investigate whether we can use __sync__ intrinsics instead of
 //                 the hand coded assembly without introducing perf regressions.
 // TODO(rmcilroy): Investigate whether we can use acquire / release versions of
 //                 exclusive load / store assembly instructions and do away with
@@ skipping 283 matching lines @@
   );  // NOLINT
 
   return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
-}  // namespace base::subtle
+}  // namespace subtle
 }  // namespace base
 
 #endif  // BASE_ATOMICOPS_INTERNALS_ARM64_GCC_H_