Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/SubtreeDisplayItem.h

Index: Source/platform/graphics/paint/SubtreeDisplayItem.h
diff --git a/Source/platform/graphics/paint/SubtreeDisplayItem.h b/Source/platform/graphics/paint/SubtreeDisplayItem.h
index efddb5edab88a954e084b6139d750d0964461f53..339f24d0c5dfce96121ef59e61a686b928287390 100644
--- a/Source/platform/graphics/paint/SubtreeDisplayItem.h
+++ b/Source/platform/graphics/paint/SubtreeDisplayItem.h
@@ -12,33 +12,23 @@
 namespace blink {
 
 class PLATFORM_EXPORT SubtreeCachedDisplayItem : public DisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(SubtreeCachedDisplayItem);
 public:
-    static PassOwnPtr<SubtreeCachedDisplayItem> create(const DisplayItemClientWrapper& client, Type type)
-    {
-        return adoptPtr(new SubtreeCachedDisplayItem(client, type));
-    }
-
-private:
     SubtreeCachedDisplayItem(const DisplayItemClientWrapper& client, Type type)
         : DisplayItem(client, type)
     {
         ASSERT(isSubtreeCachedType(type));
     }
 
+private:
     virtual void replay(GraphicsContext&) override final { ASSERT_NOT_REACHED(); }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final { ASSERT_NOT_REACHED(); }
+    void appendByMoving(DisplayItems&) override;
 };
 
 class PLATFORM_EXPORT BeginSubtreeDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(BeginSubtreeDisplayItem);
 public:
-    static PassOwnPtr<BeginSubtreeDisplayItem> create(const DisplayItemClientWrapper& client, Type type)
-    {
-        return adoptPtr(new BeginSubtreeDisplayItem(client, type));
-    }
+    void appendByMoving(DisplayItems&) override;
 
-private:
     BeginSubtreeDisplayItem(const DisplayItemClientWrapper& client, Type type)
         : PairedBeginDisplayItem(client, type)
     {
@@ -47,14 +37,9 @@ private:
 };
 
 class PLATFORM_EXPORT EndSubtreeDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndSubtreeDisplayItem);
 public:
-    static PassOwnPtr<EndSubtreeDisplayItem> create(const DisplayItemClientWrapper& client, Type type)
-    {
-        return adoptPtr(new EndSubtreeDisplayItem(client, type));
-    }
+    void appendByMoving(DisplayItems&) override;
 
-private:
     EndSubtreeDisplayItem(const DisplayItemClientWrapper& client, Type type)
         : PairedEndDisplayItem(client, type)
     {