Reland "Implement FullScreen using top layer."

third_party/WebKit/Source/core/layout/api/LayoutFullScreenItem.h

-
-// Copyright 2016 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 LayoutFullScreenItem_h
-#define LayoutFullScreenItem_h
-
-#include "core/layout/LayoutBlock.h"
-#include "core/layout/api/LayoutBlockItem.h"
-
-namespace blink {
-
-class LayoutFullScreenItem : public LayoutBlockItem {
-public:
-    explicit LayoutFullScreenItem(LayoutBlock* layoutBlock)
-        : LayoutBlockItem(layoutBlock)
-    {
-    }
-
-    explicit LayoutFullScreenItem(const LayoutBlockItem& item)
-        : LayoutBlockItem(item)
-    {
-        ASSERT_WITH_SECURITY_IMPLICATION(!item || item.isLayoutFullScreen());
-    }
-
-    explicit LayoutFullScreenItem(std::nullptr_t) : LayoutBlockItem(nullptr) { }
-
-    LayoutFullScreenItem() { }
-
-    void unwrapLayoutObject()
-    {
-        return toFullScreen()->unwrapLayoutObject();
-    }
-
-private:
-    LayoutFullScreen* toFullScreen() { return toLayoutFullScreen(layoutObject()); }
-    const LayoutFullScreen* toFullScreen() const { return toLayoutFullScreen(layoutObject()); }
-};
-
-} // namespace blink
-
-#endif // LayoutFullScreenItem_h