Skip PaintPhaseDescendantOutlinesOnly if no descendent outlines in the layer

third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

 // Copyright 2014 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 "core/paint/PaintLayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/layout/ClipPathOperation.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutFrame.h"
@@ skipping 662 matching lines @@
     }
 
     // We have to loop through every fragment multiple times, since we have to issue paint invalidations in each specific phase in order for
     // interleaving of the fragments to work properly.
     paintForegroundForFragmentsWithPhase(selectionOnly ? PaintPhaseSelection : PaintPhaseDescendantBlockBackgroundsOnly, layerFragments,
         context, localPaintingInfo, paintingRootForLayoutObject, paintFlags, clipState);
 
     if (!selectionOnly) {
         paintForegroundForFragmentsWithPhase(PaintPhaseFloat, layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags, clipState);
         paintForegroundForFragmentsWithPhase(PaintPhaseForeground, layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags, clipState);
-        paintForegroundForFragmentsWithPhase(PaintPhaseDescendantOutlinesOnly, layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags, clipState);
+
+        if (m_paintLayer.needsPaintPhaseDescendantOutlines()) {
+            size_t displayItemListSizeBefore = context.paintController().newDisplayItemList().size();
+            paintForegroundForFragmentsWithPhase(PaintPhaseDescendantOutlinesOnly, layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags, clipState);
+            if (displayItemListSizeBefore == context.paintController().newDisplayItemList().size())
+                m_paintLayer.clearNeedsPaintPhaseDescendantOutlines();
+        }
     }
 }
 
 void PaintLayerPainter::paintForegroundForFragmentsWithPhase(PaintPhase phase, const PaintLayerFragments& layerFragments, GraphicsContext& context,
     const PaintLayerPaintingInfo& localPaintingInfo, LayoutObject* paintingRootForLayoutObject, PaintLayerFlags paintFlags, ClipState clipState)
 {
     bool needsScope = layerFragments.size() > 1;
     for (auto& fragment : layerFragments) {
         if (!fragment.foregroundRect.isEmpty()) {
             Optional<ScopeRecorder> scopeRecorder;
@@ skipping 47 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize(), paintingRoot);
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink