Let synchronized painting generate correct paint invalidation rects

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

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 9187b0ba9ed49a9d287c91a905c75cd46244f9a0..d0cdd0b7d65191ac0b1c2ec801521d3cf5e297ae 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -2038,18 +2038,34 @@ void CompositedLayerMapping::setContentsNeedDisplayInRect(const LayoutRect& r, P
     ApplyToGraphicsLayers(this, functor, ApplyToContentLayers);
 }
 
-void CompositedLayerMapping::invalidateDisplayItemClient(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect)
+struct InvalidateDisplayItemClientFunctor {
+    void operator() (GraphicsLayer* layer) const
+    {
+        Vector<IntRect> layerPaintInvalidationRects;
+        for (const auto& r : paintInvalidationRects) {
+            IntRect intRect = enclosingIntRect(LayoutRect(r.location() + subpixelAccumulation, r.size()));
+            intRect.move(-layer->offsetFromLayoutObject());
+            layerPaintInvalidationRects.append(intRect);
+        }
+        layer->invalidateDisplayItemClient(displayItemClient, invalidationReason, layerPaintInvalidationRects);
+    }
+
+    const DisplayItemClientWrapper& displayItemClient;
+    PaintInvalidationReason invalidationReason;
+    Vector<LayoutRect> paintInvalidationRects;
+    LayoutSize subpixelAccumulation;
+};
+
+void CompositedLayerMapping::invalidateDisplayItemClient(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const Vector<LayoutRect>& paintInvalidationRects)
 {
-    ApplyToGraphicsLayers(this, [&displayItemClient, paintInvalidationReason, previousPaintInvalidationRect, newPaintInvalidationRect](GraphicsLayer* layer) {
-        layer->invalidateDisplayItemClient(displayItemClient, paintInvalidationReason, enclosingIntRect(previousPaintInvalidationRect), enclosingIntRect(newPaintInvalidationRect));
-    }, ApplyToContentLayers);
+    InvalidateDisplayItemClientFunctor functor = { displayItemClient, paintInvalidationReason, paintInvalidationRects, m_owningLayer.subpixelAccumulation() };
+    ApplyToGraphicsLayers(this, functor, ApplyToContentLayers);
 }
 
-void CompositedLayerMapping::invalidateDisplayItemClientOnScrollingContentsLayer(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect)
+void CompositedLayerMapping::invalidateDisplayItemClientOnScrollingContentsLayer(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const Vector<LayoutRect>& paintInvalidationRects)
 {
-    ApplyToGraphicsLayers(this, [&displayItemClient, paintInvalidationReason, previousPaintInvalidationRect, newPaintInvalidationRect](GraphicsLayer* layer) {
-        layer->invalidateDisplayItemClient(displayItemClient, paintInvalidationReason, enclosingIntRect(previousPaintInvalidationRect), enclosingIntRect(newPaintInvalidationRect));
-    }, ApplyToScrollingContentsLayer);
+    InvalidateDisplayItemClientFunctor functor = { displayItemClient, paintInvalidationReason, paintInvalidationRects, m_owningLayer.subpixelAccumulation() };
+    ApplyToGraphicsLayers(this, functor, ApplyToScrollingContentsLayer);
 }
 
 const GraphicsLayerPaintInfo* CompositedLayerMapping::containingSquashedLayer(const LayoutObject* layoutObject, const Vector<GraphicsLayerPaintInfo>& layers, unsigned maxSquashedLayerIndex)