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

Source/core/paint/SVGClipPainter.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/SVGClipPainter.h"
 
 #include "core/dom/ElementTraversal.h"
 #include "core/layout/svg/LayoutSVGResourceClipper.h"
 #include "core/layout/svg/SVGResources.h"
 #include "core/layout/svg/SVGResourcesCache.h"
 #include "core/paint/CompositingRecorder.h"
+#include "core/paint/LayoutObjectDrawingRecorder.h"
 #include "core/paint/PaintInfo.h"
 #include "core/paint/TransformRecorder.h"
 #include "platform/graphics/paint/ClipPathDisplayItem.h"
 #include "platform/graphics/paint/CompositingDisplayItem.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "wtf/TemporaryChange.h"
 
 namespace blink {
 
@@ skipping 52 matching lines @@
         // clipPath can also be clipped by another clipPath.
         SVGResources* resources = SVGResourcesCache::cachedResourcesForLayoutObject(&m_clip);
         LayoutSVGResourceClipper* clipPathClipper = resources ? resources->clipper() : 0;
         ClipperState clipPathClipperState = ClipperNotApplied;
         if (clipPathClipper && !SVGClipPainter(*clipPathClipper).applyClippingToContext(m_clip, targetBoundingBox, paintInvalidationRect, context, clipPathClipperState)) {
             // End the clip mask's compositor.
             CompositingRecorder::endCompositing(*context, target);
             return false;
         }
 
-        drawClipMaskContent(context, target, targetBoundingBox);
+        drawClipMaskContent(context, target, targetBoundingBox, paintInvalidationRect);
 
         if (clipPathClipper)
             SVGClipPainter(*clipPathClipper).postApplyStatefulResource(m_clip, context, clipPathClipperState);
     }
 
     // Masked content layer start.
     CompositingRecorder::beginCompositing(*context, target, SkXfermode::kSrcIn_Mode, 1, &paintInvalidationRect);
 
     return true;
 }
@@ skipping 17 matching lines @@
         CompositingRecorder::endCompositing(*context, target);
 
         // Transfer clip mask -> bg (SrcOver)
         CompositingRecorder::endCompositing(*context, target);
         break;
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
-void SVGClipPainter::drawClipMaskContent(GraphicsContext* context, const LayoutObject& layoutObject, const FloatRect& targetBoundingBox)
+void SVGClipPainter::drawClipMaskContent(GraphicsContext* context, const LayoutObject& layoutObject, const FloatRect& targetBoundingBox, const FloatRect& targetPaintInvalidationRect)
 {
     ASSERT(context);
 
     AffineTransform contentTransformation;
     RefPtr<const SkPicture> clipContentPicture = m_clip.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::SVGClip, clipContentPicture));
-    } else {
-        DrawingDisplayItem clipPicture(layoutObject, DisplayItem::SVGClip, clipContentPicture);
-        clipPicture.replay(*context);
-    }
+    LayoutObjectDrawingRecorder drawingRecorder(*context, layoutObject, DisplayItem::SVGClip, targetPaintInvalidationRect);
+    if (drawingRecorder.canUseCachedDrawing())
+        return;
+
+    context->save();
+    context->concatCTM(contentTransformation);
+    context->drawPicture(clipContentPicture.get());
+    context->restore();
 }
 
 }