Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/DrawingDisplayItem.h

Index: Source/platform/graphics/paint/DrawingDisplayItem.h
diff --git a/Source/platform/graphics/paint/DrawingDisplayItem.h b/Source/platform/graphics/paint/DrawingDisplayItem.h
index 3e2b721d5b64062928c3557cee82b8d5903152bb..1d373cac0b26d253e7b40c7935825a115a416774 100644
--- a/Source/platform/graphics/paint/DrawingDisplayItem.h
+++ b/Source/platform/graphics/paint/DrawingDisplayItem.h
@@ -25,21 +25,24 @@ public:
     DrawingDisplayItem(const DisplayItemClientWrapper& client, Type type, PassRefPtr<const SkPicture> picture)
         : DisplayItem(client, type)
         , m_picture(picture && picture->approximateOpCount() ? picture : nullptr)
-#if ENABLE(ASSERT)
-        , m_underInvalidationCheckingMode(CheckPicture)
-#endif
     {
         ASSERT(isDrawingType(type));
     }
 
-    static PassOwnPtr<DrawingDisplayItem> create(const DisplayItemClientWrapper& client, Type type, PassRefPtr<const SkPicture> picture)
+#if ENABLE(ASSERT)
+    DrawingDisplayItem(const DisplayItemClientWrapper& client, Type type, PassRefPtr<const SkPicture> picture, UnderInvalidationCheckingMode underInvalidationCheckingMode)
+        : DisplayItem(client, type)
+        , m_picture(picture && picture->approximateOpCount() ? picture : nullptr)
+        , m_underInvalidationCheckingMode(underInvalidationCheckingMode)
     {
-        return adoptPtr(new DrawingDisplayItem(client, type, picture));
+        ASSERT(isDrawingType(type));
     }
+#endif
 
-    virtual void replay(GraphicsContext&);
-    virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;
-    virtual bool drawsContent() const override;
+    void replay(GraphicsContext&) override;
+    void appendToWebDisplayItemList(WebDisplayItemList*) const override;
+    void appendByMoving(DisplayItems&) override;
+    bool drawsContent() const override;
 
     const SkPicture* picture() const { return m_picture.get(); }