[presubmit] Enable readability/namespace linter checking.

src/base/utils/random-number-generator.cc

 // Copyright 2013 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.
 
 #include "src/base/utils/random-number-generator.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #include <new>
@@ skipping 118 matching lines @@
   seed_ = seed;
   return static_cast<int>(seed >> (48 - bits));
 }
 
 
 void RandomNumberGenerator::SetSeed(int64_t seed) {
   initial_seed_ = seed;
   seed_ = (seed ^ kMultiplier) & kMask;
 }
 
-} }  // namespace v8::base
+}  // namespace base
+}  // namespace v8