diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index 1082a2ce4c0a..750edcbb8bc0 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -5487,7 +5487,7 @@ nsDocument::UnblockDOMContentLoaded()
 }
 
 void
-nsDocument::ContentStateChanged(nsIContent* aContent, EventStates aStateMask)
+nsIDocument::ContentStateChanged(nsIContent* aContent, EventStates aStateMask)
 {
   NS_PRECONDITION(!nsContentUtils::IsSafeToRunScript(),
                   "Someone forgot a scriptblocker");
@@ -5496,14 +5496,14 @@ nsDocument::ContentStateChanged(nsIContent* aContent, EventStates aStateMask)
 }
 
 void
-nsDocument::DocumentStatesChanged(EventStates aStateMask)
+nsIDocument::DocumentStatesChanged(EventStates aStateMask)
 {
   UpdateDocumentStates(aStateMask);
   NS_DOCUMENT_NOTIFY_OBSERVERS(DocumentStatesChanged, (this, aStateMask));
 }
 
 void
-nsDocument::StyleRuleChanged(StyleSheet* aSheet, css::Rule* aStyleRule)
+nsIDocument::StyleRuleChanged(StyleSheet* aSheet, css::Rule* aStyleRule)
 {
   if (!StyleSheetChangeEventsEnabled()) {
     return;
@@ -5516,7 +5516,7 @@ nsDocument::StyleRuleChanged(StyleSheet* aSheet, css::Rule* aStyleRule)
 }
 
 void
-nsDocument::StyleRuleAdded(StyleSheet* aSheet, css::Rule* aStyleRule)
+nsIDocument::StyleRuleAdded(StyleSheet* aSheet, css::Rule* aStyleRule)
 {
   if (!StyleSheetChangeEventsEnabled()) {
     return;
@@ -5529,7 +5529,7 @@ nsDocument::StyleRuleAdded(StyleSheet* aSheet, css::Rule* aStyleRule)
 }
 
 void
-nsDocument::StyleRuleRemoved(StyleSheet* aSheet, css::Rule* aStyleRule)
+nsIDocument::StyleRuleRemoved(StyleSheet* aSheet, css::Rule* aStyleRule)
 {
   if (!StyleSheetChangeEventsEnabled()) {
     return;
diff --git a/dom/base/nsDocument.h b/dom/base/nsDocument.h
index e957f30a7685..f0411c53a0e7 100644
--- a/dom/base/nsDocument.h
+++ b/dom/base/nsDocument.h
@@ -499,19 +499,6 @@ public:
 
   virtual void SetReadyStateInternal(ReadyState rs) override;
 
-  virtual void ContentStateChanged(nsIContent* aContent,
-                                   mozilla::EventStates aStateMask)
-                                     override;
-  virtual void DocumentStatesChanged(
-                 mozilla::EventStates aStateMask) override;
-
-  virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet,
-                                mozilla::css::Rule* aStyleRule) override;
-  virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet,
-                              mozilla::css::Rule* aStyleRule) override;
-  virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet,
-                                mozilla::css::Rule* aStyleRule) override;
-
   void FlushPendingNotifications(mozilla::FlushType aType) final;
   virtual void FlushExternalResources(mozilla::FlushType aType) override;
   virtual void SetXMLDeclaration(const char16_t *aVersion,
diff --git a/dom/base/nsIDocument.h b/dom/base/nsIDocument.h
index 91ac5b137a36..10aca432c6a3 100644
--- a/dom/base/nsIDocument.h
+++ b/dom/base/nsIDocument.h
@@ -1694,22 +1694,22 @@ public:
 
   // notify that a content node changed state.  This must happen under
   // a scriptblocker but NOT within a begin/end update.
-  virtual void ContentStateChanged(nsIContent* aContent,
-                                   mozilla::EventStates aStateMask) = 0;
+  void ContentStateChanged(
+      nsIContent* aContent, mozilla::EventStates aStateMask);
 
   // Notify that a document state has changed.
   // This should only be called by callers whose state is also reflected in the
   // implementation of nsDocument::GetDocumentState.
-  virtual void DocumentStatesChanged(mozilla::EventStates aStateMask) = 0;
+  void DocumentStatesChanged(mozilla::EventStates aStateMask);
 
   // Observation hooks for style data to propagate notifications
   // to document observers
-  virtual void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet,
-                                mozilla::css::Rule* aStyleRule) = 0;
-  virtual void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet,
-                              mozilla::css::Rule* aStyleRule) = 0;
-  virtual void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet,
-                                mozilla::css::Rule* aStyleRule) = 0;
+  void StyleRuleChanged(mozilla::StyleSheet* aStyleSheet,
+                        mozilla::css::Rule* aStyleRule);
+  void StyleRuleAdded(mozilla::StyleSheet* aStyleSheet,
+                      mozilla::css::Rule* aStyleRule);
+  void StyleRuleRemoved(mozilla::StyleSheet* aStyleSheet,
+                        mozilla::css::Rule* aStyleRule);
 
   /**
    * Flush notifications for this document and its parent documents