Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc

Index: chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
diff --git a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
index b829960180fad95137d5d39a9559e24f17d4a9b3..b27824f18679fb5a6c8b06d3bcd5937448306fb4 100644
--- a/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/last_download_finder.cc
@@ -124,9 +124,6 @@ LastDownloadFinder::LastDownloadFinder(const std::vector<Profile*>& profiles,
                               chrome::NOTIFICATION_PROFILE_ADDED,
                               content::NotificationService::AllSources());
   notification_registrar_.Add(this,
-                              chrome::NOTIFICATION_HISTORY_LOADED,
-                              content::NotificationService::AllSources());
-  notification_registrar_.Add(this,
                               chrome::NOTIFICATION_PROFILE_DESTROYED,
                               content::NotificationService::AllSources());
 
@@ -165,7 +162,10 @@ void LastDownloadFinder::SearchInProfile(Profile* profile) {
         base::Bind(&LastDownloadFinder::OnDownloadQuery,
                    weak_ptr_factory_.GetWeakPtr(),
                    profile));
-  }  // else wait until history is loaded.
+  } else {
+    // else wait until history is loaded.
+    history_service->AddHistoryServiceObserver(this);
+  }
 }
 
 void LastDownloadFinder::OnProfileHistoryLoaded(
@@ -242,10 +242,6 @@ void LastDownloadFinder::Observe(int type,
     case chrome::NOTIFICATION_PROFILE_ADDED:
       SearchInProfile(content::Source<Profile>(source).ptr());
       break;
-    case chrome::NOTIFICATION_HISTORY_LOADED:
-      OnProfileHistoryLoaded(content::Source<Profile>(source).ptr(),
-                             content::Details<HistoryService>(details).ptr());
-      break;
     case chrome::NOTIFICATION_PROFILE_DESTROYED:
       AbandonSearchInProfile(content::Source<Profile>(source).ptr());
       break;
@@ -254,4 +250,9 @@ void LastDownloadFinder::Observe(int type,
   }
 }
 
+void LastDownloadFinder::HistoryServiceLoaded(HistoryService* history_service) {
+  OnProfileHistoryLoaded(history_service->profile(), history_service);
+  history_service->RemoveHistoryServiceObserver(this);
+}
+
 }  // namespace safe_browsing