binding: Makes ExceptionState STACK_ALLOCATED().

third_party/WebKit/Source/bindings/core/v8/OnStackObjectChecker.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.
-
-#ifndef OnStackObjectChecker_h
-#define OnStackObjectChecker_h
-
-#include "core/CoreExport.h"
-#include "wtf/HashSet.h"
-#include "wtf/Noncopyable.h"
-
-namespace blink {
-
-#if ENABLE(ASSERT)
-class Dictionary;
-
-// A lifetime checker for C++ objects which must not outlive the owner of an
-// instance of this class. In general, we should rely on Oilpan or RefCounted
-// to manage object lifetime. However, we don't use them for some objects
-// (e.g. Dictionary) for performance reason. This checker is for such objects.
-// The C++ objects to be checked must call add() on creation, and remove() on
-// destruction, respectively.
-class CORE_EXPORT OnStackObjectChecker final {
-    WTF_MAKE_NONCOPYABLE(OnStackObjectChecker);
-public:
-    OnStackObjectChecker();
-    ~OnStackObjectChecker();
-
-    void add(Dictionary*);
-    void remove(Dictionary*);
-
-private:
-    HashSet<Dictionary*> m_dictionaries;
-};
-#endif
-
-} // namespace blink
-
-#endif // OnStackObjectChecker_h