Slimming Paint phase 2 compositing algorithm plumbing

Source/core/compositing/DisplayListCompositingBuilder.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 DisplayListCompositingBuilder_h
+#define DisplayListCompositingBuilder_h
+
+#include "platform/graphics/GraphicsLayer.h"
+#include "platform/graphics/paint/DisplayItemList.h"
+#include "platform/graphics/paint/DisplayItemTransformTree.h"
+
+namespace blink {
+
+struct CompositedDisplayList {
+    WTF_MAKE_NONCOPYABLE(CompositedDisplayList);
+    WTF_MAKE_FAST_ALLOCATED(CompositedDisplayList);
+public:
+    CompositedDisplayList(const DisplayItemList& displayItemList, const DisplayListDiff& displayListDiff, GraphicsLayer& rootGraphicsLayer)
+        : m_displayItemList(displayItemList)
+        , m_displayListDiff(displayListDiff)
+        , m_rootGraphicsLayer(rootGraphicsLayer) { }
+
+    const DisplayItemList& m_displayItemList;
+    const DisplayListDiff& m_displayListDiff;
+    GraphicsLayer& m_rootGraphicsLayer;
+};
+
+class DisplayListCompositingBuilder {
+public:
+    DisplayListCompositingBuilder(CompositedDisplayList& compositedDisplayList)
+        : m_compositedDisplayList(compositedDisplayList) {}
+
+    void build();
+
+private:
+    CompositedDisplayList& m_compositedDisplayList;
+};
+
+} // namespace blink
+
+#endif // DisplayListCompositingBuilder_h