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

third_party/WebKit/Source/bindings/tests/results/core/DoubleOrString.h

 // Copyright 2014 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.
 
 // This file has been auto-generated by code_generator_v8.py.
 // DO NOT MODIFY!
 
 // This file has been generated from the Jinja2 template in
 // third_party/WebKit/Source/bindings/templates/union_container.h.tmpl
 
 // clang-format off
 #ifndef DoubleOrString_h
 #define DoubleOrString_h
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/NativeValueTraits.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class CORE_EXPORT DoubleOrString final {
   DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
  public:
   DoubleOrString();
@@ skipping 40 matching lines @@
   v8SetReturnValue(callbackInfo, ToV8(impl, callbackInfo.Holder(), callbackInfo.GetIsolate()));
 }
 
 template <class CallbackInfo>
 inline void v8SetReturnValue(const CallbackInfo& callbackInfo, DoubleOrString& impl, v8::Local<v8::Object> creationContext) {
   v8SetReturnValue(callbackInfo, ToV8(impl, creationContext, callbackInfo.GetIsolate()));
 }
 
 template <>
 struct NativeValueTraits<DoubleOrString> {
+  using ImplType = DoubleOrString;
   CORE_EXPORT static DoubleOrString nativeValue(v8::Isolate*, v8::Local<v8::Value>, ExceptionState&);
 };
 
+template <>
+struct V8TypeOf<DoubleOrString> {
+  typedef V8DoubleOrString Type;
+};
+
 }  // namespace blink
 
 // We need to set canInitializeWithMemset=true because HeapVector supports
 // items that can initialize with memset or have a vtable. It is safe to
 // set canInitializeWithMemset=true for a union type object in practice.
 // See https://codereview.chromium.org/1118993002/#msg5 for more details.
 WTF_ALLOW_MOVE_AND_INIT_WITH_MEM_FUNCTIONS(blink::DoubleOrString);
 
 #endif  // DoubleOrString_h