From b72ddcf657cfc601ea9fb9ed8d46b8dc7a2fa2fa Mon Sep 17 00:00:00 2001
From: FranklinDM <mrmineshafter17@gmail.com>
Date: Sat, 4 Mar 2023 16:14:24 +0800
Subject: [PATCH] Issue #2135 - Bug 1414692: Adopt shadow roots when adopting a
 shadow host across documents

---
 dom/base/nsNodeUtils.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/dom/base/nsNodeUtils.cpp b/dom/base/nsNodeUtils.cpp
index 7d31358487..63da8b04df 100644
--- a/dom/base/nsNodeUtils.cpp
+++ b/dom/base/nsNodeUtils.cpp
@@ -650,6 +650,17 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, bool aClone, bool aDeep,
     }
   }
 
+  // TODO: update this if we choose to land bug 1393806.
+  if (aDeep && !aClone && aNode->IsElement()) {
+    if (ShadowRoot* shadowRoot = aNode->AsElement()->GetShadowRoot()) {
+      nsCOMPtr<nsINode> child;
+      rv = CloneAndAdopt(shadowRoot, aClone, aDeep, nodeInfoManager,
+                         aReparentScope, aNodesWithProperties, clone,
+                         getter_AddRefs(child));
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
   // Cloning template element.
   if (aDeep && aClone && IsTemplateElement(aNode)) {
     DocumentFragment* origContent =