[presubmit] Enable readability/namespace linter checking.

src/heap/objects-visiting.h

 // Copyright 2012 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.
 
 #ifndef V8_OBJECTS_VISITING_H_
 #define V8_OBJECTS_VISITING_H_
 
 #include "src/allocation.h"
 #include "src/heap/heap.h"
 #include "src/heap/spaces.h"
@@ skipping 473 matching lines @@
 class WeakObjectRetainer;
 
 
 // A weak list is single linked list where each element has a weak pointer to
 // the next element. Given the head of the list, this function removes dead
 // elements from the list and if requested records slots for next-element
 // pointers. The template parameter T is a WeakListVisitor that defines how to
 // access the next-element pointers.
 template <class T>
 Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer);
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_OBJECTS_VISITING_H_