diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index e282d5f72205..b98aa39c310f 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -6798,43 +6798,6 @@ CheckForWindowedPlugins(nsISupports* aSupports, void* aResult)
   }
 }
 
-static bool
-DocTreeContainsWindowedPlugins(nsIDocument* aDoc, void* aResult)
-{
-  if (!nsContentUtils::IsChromeDoc(aDoc)) {
-    aDoc->EnumerateActivityObservers(CheckForWindowedPlugins, aResult);
-  }
-  if (*static_cast<bool*>(aResult)) {
-    // Return false to stop iteration, we found a windowed plugin.
-    return false;
-  }
-  aDoc->EnumerateSubDocuments(DocTreeContainsWindowedPlugins, aResult);
-  // Return false to stop iteration if we found a windowed plugin in
-  // the sub documents.
-  return !*static_cast<bool*>(aResult);
-}
-
-/* static */
-bool
-nsContentUtils::HasPluginWithUncontrolledEventDispatch(nsIDocument* aDoc)
-{
-#ifdef XP_MACOSX
-  // We control dispatch to all mac plugins.
-  return false;
-#endif
-  bool result = false;
-  
-  // Find the top of the document's branch, the child of the chrome document.
-  nsIDocument* doc = aDoc;
-  nsIDocument* parent = nullptr;
-  while (doc && (parent = doc->GetParentDocument()) && !IsChromeDoc(parent)) {
-    doc = parent;
-  }
-
-  DocTreeContainsWindowedPlugins(doc, &result);
-  return result;
-}
-
 /* static */
 bool
 nsContentUtils::HasPluginWithUncontrolledEventDispatch(nsIContent* aContent)
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index 6d043af56203..0e8fd34f3415 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2059,14 +2059,6 @@ public:
     return sPrivacyResistFingerprinting;
   }
 
-  /**
-   * Returns true if the doc tree branch which contains aDoc contains any
-   * plugins which we don't control event dispatch for, i.e. do any plugins
-   * in the same tab as this document receive key events outside of our
-   * control? This always returns false on MacOSX.
-   */
-  static bool HasPluginWithUncontrolledEventDispatch(nsIDocument* aDoc);
-
   /**
    * Return true if this doc is controlled by a ServiceWorker.
    */