WIP bindings: Add support for the record<K,V> WebIDL type.

third_party/WebKit/Source/bindings/core/v8/NativeValueTraits.h

 // Copyright (c) 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 NativeValueTraits_h
 #define NativeValueTraits_h
 
 #include "v8/include/v8.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 class ExceptionState;
 
 template <typename T, typename... Arguments>
 struct NativeValueTraits {
   STATIC_ONLY(NativeValueTraits);
-  static T nativeValue(v8::Isolate*,

[Yuki, 2017/03/02 07:47:28]

If you'd like to remove this declaration, could you put a comment instead?

The empty struct seems meaningless.  It's unfriendly for code readers.

-                       v8::Local<v8::Value>,
-                       ExceptionState&,
-                       Arguments... args);
 };
 
 }  // namespace blink
 
 #endif  // NativeValueTraits_h