Add more missing closing namespace comments.

third_party/WebKit/Source/core/dom/WeakIdentifierMap.h

 // Copyright 2015 The Chromium 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 WeakIdentifierMap_h
 #define WeakIdentifierMap_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/Allocator.h"
 #include "wtf/HashMap.h"
@@ skipping 136 matching lines @@
     extern template class WeakIdentifierMap<T, ##__VA_ARGS__>;
 
 #define DEFINE_WEAK_IDENTIFIER_MAP(T, ...) \
     template class WeakIdentifierMap<T, ##__VA_ARGS__>; \
     template<> WeakIdentifierMap<T, ##__VA_ARGS__>& WeakIdentifierMap<T, ##__VA_ARGS__>::instance() \
     { \
         using RefType = WeakIdentifierMap<T, ##__VA_ARGS__>::ReferenceType; \
         DEFINE_STATIC_LOCAL(RefType, mapInstance, (new WeakIdentifierMap<T, ##__VA_ARGS__>())); \
         return *mapInstance; \
     }
-}
+} // namespace blink
 
 #endif // WeakIdentifierMap_h