[presubmit] Enable readability/namespace linter checking.

src/hydrogen-representation-changes.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_HYDROGEN_REPRESENTATION_CHANGES_H_
 #define V8_HYDROGEN_REPRESENTATION_CHANGES_H_
 
 #include "src/hydrogen.h"
 
 namespace v8 {
 namespace internal {
 
 
 class HRepresentationChangesPhase : public HPhase {
  public:
   explicit HRepresentationChangesPhase(HGraph* graph)
       : HPhase("H_Representation changes", graph) { }
 
   void Run();
 
  private:
   void InsertRepresentationChangeForUse(HValue* value,
                                         HValue* use_value,
                                         int use_index,
                                         Representation to);
   void InsertRepresentationChangesForValue(HValue* value);
 };
 
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_HYDROGEN_REPRESENTATION_CHANGES_H_