Make DOMTypedArray exported.

Source/bindings/core/v8/ScriptWrappable.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 198 matching lines @@
 #define DEFINE_WRAPPERTYPEINFO_NOT_REACHED() \
 public: \
     virtual const WrapperTypeInfo* wrapperTypeInfo() const override \
     { \
         ASSERT_NOT_REACHED(); \
         return 0; \
     } \
 private: \
     typedef void end_of_define_wrappertypeinfo_not_reached_t
 
+
+// Declares 'wrapperTypeInfo' method without definition.
+//
+// This macro is used for template classes. e.g. DOMTypedArray<>.
+// To export such a template class X, we need to instantiate X with EXPORT_API,
+// i.e. "extern template class EXPORT_API X;"
+// However, once we instantiate X, we cannot specialize X after
+// the instantiation. i.e. we will see "error: explicit specialization of ...
+// after instantiation". So we cannot define X's s_wrapperTypeInfo in generated
+// code by using specialization. Instead, we need to implement wrapperTypeInfo
+// in X's cpp code, and instantiate X, i.e. "template class X;".
+#define DECLARE_WRAPPERTYPEINFO() \
+public: \
+    virtual const WrapperTypeInfo* wrapperTypeInfo() const override; \
+private: \
+    typedef void end_of_define_wrappertypeinfo_not_reached_t
+
 } // namespace blink
 
 #endif // ScriptWrappable_h