[Slimming Paint] Add *FilterDisplayItem type for slimming paint

Source/core/paint/FilterPainter.h

Index: Source/core/paint/FilterPainter.h
diff --git a/Source/core/paint/FilterPainter.h b/Source/core/paint/FilterPainter.h
index 7bcb140f44ca335eaa9d062410a5ad7091de2ac6..3af6ab56a0b6364344e489a33c00aa62dc065a4f 100644
--- a/Source/core/paint/FilterPainter.h
+++ b/Source/core/paint/FilterPainter.h
@@ -5,6 +5,7 @@
 #ifndef FilterPainter_h
 #define FilterPainter_h
 
+#include "core/paint/ViewDisplayList.h"
 #include "core/rendering/LayerPaintingInfo.h"
 #include "wtf/OwnPtr.h"
 
@@ -16,6 +17,31 @@ class FloatRect;
 class GraphicsContext;
 class RenderLayer;
 
+class BeginFilterDisplayItem : public DisplayItem {
+public:
+    BeginFilterDisplayItem(const RenderObject* renderer, Type type, PassRefPtr<ImageFilter> imageFilter, const LayoutRect& bounds)
+        : DisplayItem(renderer, type), m_imageFilter(imageFilter), m_bounds(bounds) { }
+    virtual void replay(GraphicsContext*) override;
+
+#ifndef NDEBUG
+    virtual WTF::String asDebugString() const override;
+#endif
+
+    RefPtr<ImageFilter> m_imageFilter;
+    const LayoutRect m_bounds;
+};
+
+class EndFilterDisplayItem : public DisplayItem {
+public:
+    EndFilterDisplayItem(const RenderObject* renderer)
+        : DisplayItem(renderer, EndFilter) { }
+    virtual void replay(GraphicsContext*) override;
+
+#ifndef NDEBUG
+    virtual WTF::String asDebugString() const override;
+#endif
+};
+
 class FilterPainter {
 public:
     FilterPainter(RenderLayer&, GraphicsContext*, const LayoutPoint& offsetFromRoot, const ClipRect&, LayerPaintingInfo&, PaintLayerFlags paintFlags, LayoutRect& rootRelativeBounds, bool& rootRelativeBoundsComputed);
@@ -25,6 +51,7 @@ private:
     bool m_filterInProgress;
     GraphicsContext* m_context;
     OwnPtr<ClipRecorder> m_clipRecorder;
+    RenderObject* m_renderer;
 };
 
 } // namespace blink