[Reland] Correct fixed-position recording for Slimming Paint

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index ff44d9518b245f6da1df575f356eae31c304310e..42299e6ca972a7887e4ea34179f8627f9a1a8637 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -1215,6 +1215,28 @@ void LayoutObject::invalidateDisplayItemClient(const DisplayItemClientWrapper& d
     }
 }
 
+static void invalidateDisplayItemClientForNonCompositingDescendantsRecursive(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutObject& layoutObject)
+{
+    paintInvalidationContainer.invalidateDisplayItemClientOnBacking(layoutObject);
+    for (LayoutObject* child = layoutObject.slowFirstChild(); child; child = child->nextSibling()) {
+        if (!child->isPaintInvalidationContainer())
+            invalidateDisplayItemClientForNonCompositingDescendantsRecursive(paintInvalidationContainer, *child);
+    }
+}
+
+void LayoutObject::invalidateDisplayItemClientForNonCompositingDescendants() const
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
+
+    // Not using enclosingCompositedContainer() directly because this object may be in an orphaned subtree.
+    if (const DeprecatedPaintLayer* enclosingLayer = this->enclosingLayer()) {
+        // This is valid because we want to invalidate the client in the display item list of the current backing.
+        DisableCompositingQueryAsserts disabler;
+        if (const DeprecatedPaintLayer* paintInvalidationLayer = enclosingLayer->enclosingLayerForPaintInvalidationCrossingFrameBoundaries())
+            invalidateDisplayItemClientForNonCompositingDescendantsRecursive(*paintInvalidationLayer->layoutObject(), *this);
+    }
+}
+
 void LayoutObject::invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) const
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());