[presubmit] Enable readability/namespace linter checking.

src/layout-descriptor-inl.h

 // Copyright 2014 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_LAYOUT_DESCRIPTOR_INL_H_
 #define V8_LAYOUT_DESCRIPTOR_INL_H_
 
 #include "src/layout-descriptor.h"
 
 namespace v8 {
@@ skipping 232 matching lines @@
 
 bool LayoutDescriptorHelper::IsTagged(int offset_in_bytes) {
   DCHECK(IsAligned(offset_in_bytes, kPointerSize));
   if (all_fields_tagged_) return true;
   // Object headers do not contain non-tagged fields.
   if (offset_in_bytes < header_size_) return true;
   int field_index = (offset_in_bytes - header_size_) / kPointerSize;
 
   return layout_descriptor_->IsTagged(field_index);
 }
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_LAYOUT_DESCRIPTOR_INL_H_