Add support for IsGarbageCollectedType<void>

third_party/WebKit/Source/platform/heap/Handle.h

 /*
  * Copyright (C) 2014 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 1141 matching lines @@
 }
 
 template<typename T> inline T* getPtr(const blink::Persistent<T>& p)
 {
     return p.get();
 }
 
 // For wtf/Functional.h
 template<typename T, bool isGarbageCollected> struct PointerParamStorageTraits;
 
+// The condition of 'T must be fully defined' (except for void) is checked in
+// blink::IsGarbageCollectedType<T>::value.
 template<typename T>
 struct PointerParamStorageTraits<T*, false> {
     STATIC_ONLY(PointerParamStorageTraits);
-    static_assert(sizeof(T), "T must be fully defined");
     using StorageType = T*;
 
     static StorageType wrap(T* value) { return value; }
     static T* unwrap(const StorageType& value) { return value; }
 };
 
 template<typename T>
 struct PointerParamStorageTraits<T*, true> {
     STATIC_ONLY(PointerParamStorageTraits);
-    static_assert(sizeof(T), "T must be fully defined");
     using StorageType = blink::CrossThreadPersistent<T>;
 
     static StorageType wrap(T* value) { return value; }
     static T* unwrap(const StorageType& value) { return value.get(); }
 };
 
 template<typename T>
 struct ParamStorageTraits<T*> : public PointerParamStorageTraits<T*, blink::IsGarbageCollectedType<T>::value> {
     STATIC_ONLY(ParamStorageTraits);
-    static_assert(sizeof(T), "T must be fully defined");
 };
 
 template<typename T>
 struct ParamStorageTraits<blink::WeakPersistentThisPointer<T>> {
     STATIC_ONLY(ParamStorageTraits);
     static_assert(sizeof(T), "T must be fully defined");
     using StorageType = blink::WeakPersistent<T>;
 
     static StorageType wrap(const blink::WeakPersistentThisPointer<T>& value) { return value.value(); }
 
@@ skipping 17 matching lines @@
     // into it.
     //
     // TODO(sof): remove this hack once wtf/Functional.h can also work with a type like
     // CrossThreadWeakPersistent<>.
     static WeakPtr<T> unwrap(const StorageType& value) { return WeakPtr<T>(WeakReference<T>::create(value.get())); }
 };
 
 } // namespace WTF
 
 #endif