Move core/layout/style to core/style

Source/core/layout/style/DataEquivalency.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 DataEquivalency_h
-#define DataEquivalency_h
-
-#include "wtf/OwnPtr.h"
-#include "wtf/RefPtr.h"
-
-namespace blink {
-
-template <typename T>
-bool dataEquivalent(const T* a, const T* b)
-{
-    if (a == b)
-        return true;
-    if (!a || !b)
-        return false;
-    return *a == *b;
-}
-
-template <typename T>
-bool dataEquivalent(const RefPtr<T>& a, const RefPtr<T>& b)
-{
-    return dataEquivalent(a.get(), b.get());
-}
-
-template <typename T>
-bool dataEquivalent(const Persistent<T>& a, const Persistent<T>& b)
-{
-    return dataEquivalent(a.get(), b.get());
-}
-
-template <typename T>
-bool dataEquivalent(const Member<T>& a, const Member<T>& b)
-{
-    return dataEquivalent(a.get(), b.get());
-}
-
-template <typename T>
-bool dataEquivalent(const OwnPtr<T>& a, const OwnPtr<T>& b)
-{
-    return dataEquivalent(a.get(), b.get());
-}
-
-} // namespace blink
-
-#endif // DataEquivalency_h