[Slimming Paint] Blink-side contiguous allocation of display items.

Source/core/paint/SVGMaskPainter.cpp

Index: Source/core/paint/SVGMaskPainter.cpp
diff --git a/Source/core/paint/SVGMaskPainter.cpp b/Source/core/paint/SVGMaskPainter.cpp
index 6b4e4d75005268129d93c8fc9bfa42f28e369e53..d6bb8ecd7e8406b18929fda83d7b084288318535 100644
--- a/Source/core/paint/SVGMaskPainter.cpp
+++ b/Source/core/paint/SVGMaskPainter.cpp
@@ -28,13 +28,13 @@ bool SVGMaskPainter::prepareEffect(const LayoutObject& object, GraphicsContext*
     if (paintInvalidationRect.isEmpty() || !m_mask.element()->hasChildren())
         return false;
 
+    BeginCompositingDisplayItem beginCompositingContent(object, SkXfermode::kSrcOver_Mode, 1, &paintInvalidationRect);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(context->displayItemList());
         if (context->displayItemList()->displayItemConstructionIsDisabled())
             return true;
-        context->displayItemList()->add(BeginCompositingDisplayItem::create(object, SkXfermode::kSrcOver_Mode, 1, &paintInvalidationRect));
+        context->displayItemList()->add(beginCompositingContent);
     } else {
-        BeginCompositingDisplayItem beginCompositingContent(object, SkXfermode::kSrcOver_Mode, 1, &paintInvalidationRect);
         beginCompositingContent.replay(*context);
     }
 
@@ -55,13 +55,13 @@ void SVGMaskPainter::finishEffect(const LayoutObject& object, GraphicsContext* c
         drawMaskForLayoutObject(context, object, object.objectBoundingBox());
     }
 
+    EndCompositingDisplayItem endCompositingContent(object);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(context->displayItemList());
         if (context->displayItemList()->displayItemConstructionIsDisabled())
             return;
-        context->displayItemList()->add(EndCompositingDisplayItem::create(object));
+        context->displayItemList()->add(endCompositingContent);
     } else {
-        EndCompositingDisplayItem endCompositingContent(object);
         endCompositingContent.replay(*context);
     }
 }
@@ -73,14 +73,14 @@ void SVGMaskPainter::drawMaskForLayoutObject(GraphicsContext* context, const Lay
     AffineTransform contentTransformation;
     RefPtr<const SkPicture> maskContentPicture = m_mask.createContentPicture(contentTransformation, targetBoundingBox, context);
 
+    DrawingDisplayItem maskPicture(layoutObject, DisplayItem::SVGMask, maskContentPicture);
     TransformRecorder recorder(*context, layoutObject, contentTransformation);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(context->displayItemList());
         if (context->displayItemList()->displayItemConstructionIsDisabled())
             return;
-        context->displayItemList()->add(DrawingDisplayItem::create(layoutObject, DisplayItem::SVGMask, maskContentPicture));
+        context->displayItemList()->add(maskPicture);
     } else {
-        DrawingDisplayItem maskPicture(layoutObject, DisplayItem::SVGClip, maskContentPicture);
         maskPicture.replay(*context);
     }
 }