Bug 1409249: Follow-up: Fix Android build bustage. r=bustage

MozReview-Commit-ID: 1I3z8Oqz9Qm

mobile/android/components/build/nsAndroidHistory.cpp

@@ -30,7 +30,7 @@ NS_IMPL_ISUPPORTS(nsAndroidHistory, IHistory, nsIRunnable, nsITimerCallback, nsI
 nsAndroidHistory* nsAndroidHistory::sHistory = nullptr;
 
 /*static*/
-nsAndroidHistory*
+already_AddRefed<nsAndroidHistory>
 nsAndroidHistory::GetSingleton()
 {
   if (!sHistory) {
@@ -38,8 +38,7 @@ nsAndroidHistory::GetSingleton()
     NS_ENSURE_TRUE(sHistory, nullptr);
   }
 
-  NS_ADDREF(sHistory);
-  return sHistory;
+  return do_AddRef(sHistory);
 }
 
 nsAndroidHistory::nsAndroidHistory()

mobile/android/components/build/nsAndroidHistory.h

@@ -40,7 +40,7 @@ public:
    * Obtains a pointer that has had AddRef called on it.  Used by the service
    * manager only.
    */
-  static nsAndroidHistory* GetSingleton();
+  static already_AddRefed<nsAndroidHistory> GetSingleton();
 
   nsAndroidHistory();