[presubmit] Enable readability/namespace linter checking.

src/splay-tree-inl.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.
 
 #ifndef V8_SPLAY_TREE_INL_H_
 #define V8_SPLAY_TREE_INL_H_
 
 #include "src/splay-tree.h"
 
 namespace v8 {
@@ skipping 272 matching lines @@
   int pos = 0;
   while (pos < nodes_to_visit.length()) {
     Node* node = nodes_to_visit[pos++];
     if (node->left() != NULL) nodes_to_visit.Add(node->left(), allocator_);
     if (node->right() != NULL) nodes_to_visit.Add(node->right(), allocator_);
     callback->Call(node);
   }
 }
 
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_SPLAY_TREE_INL_H_