[presubmit] Enable readability/namespace linter checking.

src/libplatform/worker-thread.h

 // 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.
 
 #ifndef V8_LIBPLATFORM_WORKER_THREAD_H_
 #define V8_LIBPLATFORM_WORKER_THREAD_H_
 
 #include <queue>
 
 #include "src/base/macros.h"
@@ skipping 14 matching lines @@
   void Run() override;
 
  private:
   friend class QuitTask;
 
   TaskQueue* queue_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkerThread);
 };
 
-} }  // namespace v8::platform
+}  // namespace platform
+}  // namespace v8
 
 
 #endif  // V8_LIBPLATFORM_WORKER_THREAD_H_