Revert "Correct fixed-position recording for Slimming Paint"

Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h

-// Copyright 2015 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 FixedPositionContainerDisplayItem_h
-#define FixedPositionContainerDisplayItem_h
-
-#include "platform/geometry/LayoutSize.h"
-#include "platform/graphics/paint/DisplayItem.h"
-#include "wtf/FastAllocBase.h"
-#include "wtf/PassOwnPtr.h"
-
-namespace blink {
-
-class PLATFORM_EXPORT BeginFixedPositionContainerDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(BeginFixedPositionContainerDisplayItem);
-public:
-    static PassOwnPtr<BeginFixedPositionContainerDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new BeginFixedPositionContainerDisplayItem(client));
-    }
-
-    BeginFixedPositionContainerDisplayItem(const DisplayItemClientWrapper& client)
-        : PairedBeginDisplayItem(client, BeginFixedPositionContainer)
-    {
-    }
-
-    virtual void replay(GraphicsContext&) override final { }
-    virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;
-};
-
-class PLATFORM_EXPORT EndFixedPositionContainerDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndFixedPositionContainerDisplayItem);
-public:
-    static PassOwnPtr<EndFixedPositionContainerDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new EndFixedPositionContainerDisplayItem(client));
-    }
-
-    EndFixedPositionContainerDisplayItem(const DisplayItemClientWrapper& client)
-        : PairedEndDisplayItem(client, EndFixedPositionContainer)
-    {
-    }
-
-    virtual void replay(GraphicsContext&) override final { }
-    virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;
-
-private:
-#if ENABLE(ASSERT)
-    virtual bool isEndAndPairedWith(const DisplayItem& other) const override final { return other.type() == BeginFixedPositionContainer; }
-#endif
-};
-
-} // namespace blink
-
-#endif // FixedPositionContainerDisplayItem_h