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 <map>
 #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 "chrome/browser/safe_browsing/incident_reporting/download_metadata_manager.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:
   typedef base::Callback<void(
       content::BrowserContext* context,
       const DownloadMetadataManager::GetDownloadDetailsCallback&)>
       DownloadDetailsGetter;
 
   // 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>)>
@@ skipping 59 matching lines @@
       std::map<Profile*, ProfileWaitState>::iterator iter);
 
   // Invokes the caller-supplied callback with the download found.
   void ReportResults();
 
   // content::NotificationObserver methods.
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
+  // history::HistoryServiceObserver:
+  void OnHistoryServiceLoaded(HistoryService* service) override;
+  void HistoryServiceBeingDeleted(HistoryService* history_service) override;
+
   // Caller-supplied callback to make an asynchronous request for a profile's
   // persistent download details.
   DownloadDetailsGetter download_details_getter_;
 
   // Caller-supplied callback to be invoked when the most recent download is
   // found.
   LastDownloadCallback callback_;
 
   // A mapping of profiles for which a download query is pending to their
   // respective states.
   std::map<Profile*, ProfileWaitState> profile_states_;
 
   // Registrar for observing profile lifecycle notifications.
   content::NotificationRegistrar notification_registrar_;
 
   // The most interesting download details retrieved from download metadata.
   scoped_ptr<ClientIncidentReport_DownloadDetails> details_;
 
   // The most recent download, updated progressively as query results arrive.
   history::DownloadRow most_recent_row_;
 
+  // HistoryServiceObserver
+  ScopedObserver<HistoryService, HistoryServiceObserver>
+      history_service_observer_;
+
   // A factory for asynchronous operations on profiles' HistoryService.
   base::WeakPtrFactory<LastDownloadFinder> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LastDownloadFinder);
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_LAST_DOWNLOAD_FINDER_H_