Use-count composited reflection.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 494 matching lines @@
     if (hasClippingLayer())
         clippingLayer()->setMaskLayer(layerToApplyChildClippingMask == clippingLayer() ? m_childClippingMaskLayer.get() : nullptr);
     if (hasScrollingLayer())
         scrollingLayer()->setMaskLayer(layerToApplyChildClippingMask == scrollingLayer() ? m_childClippingMaskLayer.get() : nullptr);
     m_graphicsLayer->setContentsClippingMaskLayer(shouldApplyChildClippingMaskOnContents ? m_childClippingMaskLayer.get() : nullptr);
 
     if (m_owningLayer.reflectionInfo() && !RuntimeEnabledFeatures::cssBoxReflectFilterEnabled()) {
         if (m_owningLayer.reflectionInfo()->reflectionLayer()->hasCompositedLayerMapping()) {
             GraphicsLayer* reflectionLayer = m_owningLayer.reflectionInfo()->reflectionLayer()->compositedLayerMapping()->mainGraphicsLayer();
             m_graphicsLayer->setReplicatedByLayer(reflectionLayer);
+            UseCounter::count(m_owningLayer.layoutObject()->document(), UseCounter::CompositedReplication);
         }
     } else {
         m_graphicsLayer->setReplicatedByLayer(nullptr);
     }
 
     updateBackgroundColor();
 
     if (layoutObject->isImage()) {
         if (isDirectlyCompositedImage()) {
             updateImageContents();
@@ skipping 2050 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink