[presubmit] Enable readability/namespace linter checking.

src/base/atomicops_internals_arm_gcc.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.
 //
 // LinuxKernelCmpxchg and Barrier_AtomicIncrement are from Google Gears.
 
 #ifndef V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_
 #define V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_
@@ skipping 278 matching lines @@
 }
 
 // Byte accessors.
 
 inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
   *ptr = value;
 }
 
 inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) { return *ptr; }
 
-} }  // namespace v8::base
+}  // namespace base
+}  // namespace v8
 
 #endif  // V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_