Bug 1629668 - Remove DocGroup::ClearEventTarget(). r=farre

Differential Revision: https://phabricator.services.mozilla.com/D70733

--HG--
extra : moz-landing-system : lando

dom/base/DocGroup.cpp

@@ -382,10 +382,5 @@ bool DocGroup::IsActive() const {
   return false;
 }
 
-void DocGroup::ClearEventTarget() {
-  nsCOMPtr<LabellingEventTarget> target = do_QueryInterface(mEventTarget);
-  target->ClearDocGroup();
-}
-
 }  // namespace dom
 }  // namespace mozilla

dom/base/DocGroup.h

@@ -130,8 +130,6 @@ class DocGroup final {
 
   bool IsEmpty() const { return mDocuments.IsEmpty(); }
 
-  void ClearEventTarget();
-
  private:
   DocGroup(BrowsingContextGroup* aBrowsingContextGroup, const nsACString& aKey);