1 files changed, 14 insertions, 5 deletions
diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 9efa01439..9f9c8e6c0 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1687,7 +1687,8 @@ Element::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
   if (CustomElementRegistry::IsCustomElementEnabled() && IsInComposedDoc()) {
     // Connected callback must be enqueued whenever a custom element becomes
     // connected.
-    if (GetCustomElementData()) {
+    CustomElementData* data = GetCustomElementData();
+    if (data && data->mState == CustomElementData::State::eCustom) {
       nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eConnected, this);
     }
   }
@@ -1985,10 +1986,12 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent)
 
      // Disconnected must be enqueued whenever a connected custom element becomes
      // disconnected.
-    if (CustomElementRegistry::IsCustomElementEnabled() &&
-        GetCustomElementData()) {
-      nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eDisconnected,
-                                               this);
+    if (CustomElementRegistry::IsCustomElementEnabled()) {
+      CustomElementData* data  = GetCustomElementData();
+      if (data && data->mState == CustomElementData::State::eCustom) {
+        nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eDisconnected,
+                                                 this);
+      }
     }
   }
 
@@ -2589,6 +2592,9 @@ Element::SetAttrAndNotify(int32_t aNamespaceID,
             nsContentUtils::GetElementDefinitionIfObservingAttr(this,
                                                                 data->mType,
                                                                 aName)) {
+        MOZ_ASSERT(data->mState == CustomElementData::State::eCustom,
+                   "AttributeChanged callback should fire only if "
+                   "custom element state is custom");
         nsCOMPtr<nsIAtom> oldValueAtom = oldValue->GetAsAtom();
         nsCOMPtr<nsIAtom> newValueAtom = valueForAfterSetAttr.GetAsAtom();
         nsAutoString ns;
@@ -2856,6 +2862,9 @@ Element::UnsetAttr(int32_t aNameSpaceID, nsIAtom* aName,
             nsContentUtils::GetElementDefinitionIfObservingAttr(this,
                                                                 data->mType,
                                                                 aName)) {
+        MOZ_ASSERT(data->mState == CustomElementData::State::eCustom,
+                   "AttributeChanged callback should fire only if "
+                   "custom element state is custom");
         nsAutoString ns;
         nsContentUtils::NameSpaceManager()->GetNameSpaceURI(aNameSpaceID, ns);