From 9adcf4429d36716fb3fd70ef0a230e725865d8be Mon Sep 17 00:00:00 2001
From: wolfbeast <mcwerewolf@wolfbeast.com>
Date: Sat, 19 Jan 2019 11:36:47 +0100
Subject: Actually unlink targets from registered intersection observers.

When a node is released/removed, and it has an intersection observer
attached to it, that observer should be unlinked at the time of release.

This resolves #935.
---
 dom/base/nsNodeUtils.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'dom/base')

diff --git a/dom/base/nsNodeUtils.cpp b/dom/base/nsNodeUtils.cpp
index ecea95dc1..75d408151 100644
--- a/dom/base/nsNodeUtils.cpp
+++ b/dom/base/nsNodeUtils.cpp
@@ -297,6 +297,16 @@ nsNodeUtils::LastRelease(nsINode* aNode)
                                          NodeWillBeDestroyed, (aNode));
     }
 
+    if (aNode->IsElement()) {
+      Element* elem = aNode->AsElement();
+      FragmentOrElement::nsDOMSlots* domSlots =
+        static_cast<FragmentOrElement::nsDOMSlots*>(slots);
+      for (auto iter = domSlots->mRegisteredIntersectionObservers.Iter(); !iter.Done(); iter.Next()) {
+        DOMIntersectionObserver* observer = iter.Key();
+        observer->UnlinkTarget(*elem);
+      }
+    }
+
     delete slots;
     aNode->mSlots = nullptr;
   }
-- 
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