diff --git a/dom/events/DOMEventTargetHelper.h b/dom/events/DOMEventTargetHelper.h
index f41eb5771301..7978f926ff38 100644
--- a/dom/events/DOMEventTargetHelper.h
+++ b/dom/events/DOMEventTargetHelper.h
@@ -43,6 +43,13 @@ public:
   {
     BindToOwner(aWindow);
   }
+  explicit DOMEventTargetHelper(nsIGlobalObject* aGlobalObject)
+    : mParentObject(nullptr)
+    , mOwnerWindow(nullptr)
+    , mHasOrHasHadOwnerWindow(false)
+  {
+    BindToOwner(aGlobalObject);
+  }
   explicit DOMEventTargetHelper(DOMEventTargetHelper* aOther)
     : mParentObject(nullptr)
     , mOwnerWindow(nullptr)
diff --git a/dom/workers/DataStore.cpp b/dom/workers/DataStore.cpp
index adb5814f38ad..f611402293af 100644
--- a/dom/workers/DataStore.cpp
+++ b/dom/workers/DataStore.cpp
@@ -29,7 +29,7 @@ NS_INTERFACE_MAP_BEGIN(WorkerDataStore)
 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
 
 WorkerDataStore::WorkerDataStore(WorkerGlobalScope* aScope)
-  : DOMEventTargetHelper(aScope)
+  : DOMEventTargetHelper(static_cast<DOMEventTargetHelper*>(aScope))
 {}
 
 already_AddRefed<WorkerDataStore>