[presubmit] Enable readability/namespace linter checking.

test/cctest/expression-type-collector.h

 // Copyright 2015 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_EXPRESSION_TYPE_COLLECTOR_H_
 #define V8_EXPRESSION_TYPE_COLLECTOR_H_
 
 #include "src/ast-expression-visitor.h"
 
 namespace v8 {
@@ skipping 15 matching lines @@
   ExpressionTypeCollector(Isolate* isolate, Zone* zone, FunctionLiteral* root,
                           ZoneVector<ExpressionTypeEntry>* dst);
   void Run();
 
  protected:
   void VisitExpression(Expression* expression);
 
  private:
   ZoneVector<ExpressionTypeEntry>* result_;
 };
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_EXPRESSION_TYPE_COLLECTOR_H_