Calculate and track display item opaqueness

third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h

Index: third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h
diff --git a/third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h b/third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h
index c9e0e9d17012cbd3c288b49e2acb172d2999755b..5ba038079482d5cd8ec1b041cfdbb9787309baee 100644
--- a/third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h
+++ b/third_party/WebKit/Source/core/paint/LayoutObjectDrawingRecorder.h
@@ -57,6 +57,8 @@ public:
     LayoutObjectDrawingRecorder(GraphicsContext& context, const LayoutObject& layoutObject, PaintPhase phase, const IntRect& clip, const LayoutPoint& paintOffset)
         : LayoutObjectDrawingRecorder(context, layoutObject, DisplayItem::paintPhaseToDrawingType(phase), FloatRect(clip), paintOffset) { }
 
+    void setKnownToBeOpaque() { ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled()); m_drawingRecorder->setKnownToBeOpaque(); }
+
 #if ENABLE(ASSERT)
     void setUnderInvalidationCheckingMode(DrawingDisplayItem::UnderInvalidationCheckingMode mode) { m_drawingRecorder->setUnderInvalidationCheckingMode(mode); }
 #endif