Bug 1278831 - PermissionStatus must keep itself alive when it has a event listener, r=smaug

dom/permission/PermissionStatus.cpp

@@ -35,6 +35,7 @@ PermissionStatus::PermissionStatus(nsPIDOMWindowInner* aWindow,
   , mName(aName)
   , mState(PermissionState::Denied)
 {
+  KeepAliveIfHasListenersFor(NS_LITERAL_STRING("change"));
 }
 
 nsresult
@@ -125,5 +126,18 @@ PermissionStatus::PermissionChanged()
   }
 }
 
+void
+PermissionStatus::DisconnectFromOwner()
+{
+  IgnoreKeepAliveIfHasListenersFor(NS_LITERAL_STRING("change"));
+
+  if (mObserver) {
+    mObserver->RemoveSink(this);
+    mObserver = nullptr;
+  }
+
+  DOMEventTargetHelper::DisconnectFromOwner();
+}
+
 } // namespace dom
 } // namespace mozilla

dom/permission/PermissionStatus.h

@@ -33,6 +33,9 @@ public:
 
   IMPL_EVENT_HANDLER(change)
 
+  void
+  DisconnectFromOwner() override;
+
 private:
   ~PermissionStatus();