Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/safe_browsing/incident_reporting/last_download_finder.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_LAST_DOWNLOAD_FINDER_H_
 #define CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_LAST_DOWNLOAD_FINDER_H_
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "chrome/browser/history/download_row.h"
+#include "components/history/core/browser/history_service_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class HistoryService;
 class Profile;
 
 namespace content {
 class NotificationDetails;
 class NotificationSource;
 }
 
 namespace history {
 struct DownloadRow;
 }
 
 namespace safe_browsing {
 
 class ClientIncidentReport_DownloadDetails;
 
 // Finds the most recent executable downloaded by any on-the-record profile with
 // history that participates in safe browsing.
-class LastDownloadFinder : public content::NotificationObserver {
+class LastDownloadFinder : public content::NotificationObserver,
+                           public history::HistoryServiceObserver {
  public:
   // The type of a callback run by the finder upon completion. The argument is a
   // protobuf containing details of the download that was found, or an empty
   // pointer if none was found.
   typedef base::Callback<void(scoped_ptr<ClientIncidentReport_DownloadDetails>)>
       LastDownloadCallback;
 
   ~LastDownloadFinder() override;
 
   // Initiates an asynchronous search for the most recent download. |callback|
   // will be run when the search is complete. The returned instance can be
   // deleted to terminate the search, in which case |callback| is not invoked.
   // Returns NULL without running |callback| if there are no eligible profiles
   // to search.
   static scoped_ptr<LastDownloadFinder> Create(
       const LastDownloadCallback& callback);
 
+  // history::HistoryServiceObserver:
+  void OnHistoryServiceLoaded(HistoryService* service) override;
+
  protected:
   // Protected constructor so that unit tests can create a fake finder.
   LastDownloadFinder();
 
  private:
   LastDownloadFinder(const std::vector<Profile*>& profiles,
                      const LastDownloadCallback& callback);
 
   // Adds |profile| to the set of profiles to be searched if it is an
   // on-the-record profile with history that participates in safe browsing. The
@@ skipping 37 matching lines @@
 
   // Registrar for observing profile lifecycle notifications.
   content::NotificationRegistrar notification_registrar_;
 
   // The most recent download, updated progressively as query results arrive.
   history::DownloadRow most_recent_row_;
 
   // A factory for asynchronous operations on profiles' HistoryService.
   base::WeakPtrFactory<LastDownloadFinder> weak_ptr_factory_;
 
+  // HistoryServiceObserver
+  ScopedObserver<HistoryService, HistoryServiceObserver>
+      history_service_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(LastDownloadFinder);
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_LAST_DOWNLOAD_FINDER_H_