Do not emit display items for masks and clips that are already cached

Source/core/paint/SVGMaskPainter.cpp

 // 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.
 
 #include "config.h"
 #include "core/paint/SVGMaskPainter.h"
 
 #include "core/layout/svg/LayoutSVGResourceMasker.h"
 #include "core/paint/CompositingRecorder.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 34 matching lines @@
 {
     ASSERT(context);
     ASSERT(m_mask.style());
     ASSERT_WITH_SECURITY_IMPLICATION(!m_mask.needsLayout());
 
     FloatRect paintInvalidationRect = object.paintInvalidationRectInLocalCoordinates();
     {
         ColorFilter maskLayerFilter = m_mask.style()->svgStyle().maskType() == MT_LUMINANCE
             ? ColorFilterLuminanceToAlpha : ColorFilterNone;
         CompositingRecorder maskCompositing(*context, object, SkXfermode::kDstIn_Mode, 1, &paintInvalidationRect, maskLayerFilter);
-        drawMaskForLayoutObject(context, object, object.objectBoundingBox());
+        drawMaskForLayoutObject(context, object, object.objectBoundingBox(), paintInvalidationRect);
     }
 
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(context->displayItemList());
         if (context->displayItemList()->displayItemConstructionIsDisabled())
             return;
         context->displayItemList()->add(EndCompositingDisplayItem::create(object));
     } else {
         EndCompositingDisplayItem endCompositingContent(object);
         endCompositingContent.replay(*context);
     }
 }
 
-void SVGMaskPainter::drawMaskForLayoutObject(GraphicsContext* context, const LayoutObject& layoutObject, const FloatRect& targetBoundingBox)
+void SVGMaskPainter::drawMaskForLayoutObject(GraphicsContext* context, const LayoutObject& layoutObject, const FloatRect& targetBoundingBox, const FloatRect& targetPaintInvalidationRect)
 {
     ASSERT(context);
 
     AffineTransform contentTransformation;
     RefPtr<const SkPicture> maskContentPicture = m_mask.createContentPicture(contentTransformation, targetBoundingBox, context);
 
-    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));
-    } else {
-        DrawingDisplayItem maskPicture(layoutObject, DisplayItem::SVGClip, maskContentPicture);
-        maskPicture.replay(*context);
-    }
+    LayoutObjectDrawingRecorder drawingRecorder(*context, layoutObject, DisplayItem::SVGMask, targetPaintInvalidationRect);
+    if (drawingRecorder.canUseCachedDrawing())
+        return;
+
+    context->save();
+    context->concatCTM(contentTransformation);
+    context->drawPicture(maskContentPicture.get());
+    context->restore();
 }
 
 }