Topsites become keyedService based.

chrome/browser/history/chrome_history_client.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_HISTORY_CHROME_HISTORY_CLIENT_H_
 #define CHROME_BROWSER_HISTORY_CHROME_HISTORY_CLIENT_H_
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "components/history/core/browser/history_client.h"
 #include "components/history/core/browser/top_sites_observer.h"
 
 class BookmarkModel;
 class HistoryService;
 class Profile;
 
 namespace history {
 class TopSites;
 }
@@ skipping 19 matching lines @@
   void Shutdown() override;
 
   // TopSitesObserver:
   void TopSitesLoaded(history::TopSites* top_sites) override;
   void TopSitesChanged(history::TopSites* top_sites) override;
 
  private:
   // The BookmarkModel, this should outlive ChromeHistoryClient.
   BookmarkModel* bookmark_model_;
   Profile* profile_;
   // The TopSites object is owned by the Profile (see

[sdefresne, 2014/12/29 09:48:14]

You can remove that comment since 1. you're using a scoped_refptr, 2. TopSites
is a KeyedService and the proper dependency is declared between the factories so
the lifetime are enforced.

[Jitu( very slow this week), 2014/12/30 10:09:03]

Done.

   // chrome/browser/profiles/profile_impl.h)
   // and lazily constructed by the  getter.
   // ChromeHistoryClient is a KeyedService linked to the Profile lifetime by the
   // ChromeHistoryClientFactory (which is a BrowserContextKeyedServiceFactory).
   // Before the Profile is destroyed, all the KeyedService Shutdown methods are
   // called, and the Profile is fully constructed before any of the KeyedService
   // can  be constructed. The TopSites does not use the HistoryService nor the
   // HistoryClient during construction (it uses it later, but supports getting
   // an NULL  pointer).
-  history::TopSites* top_sites_;
+  scoped_refptr<history::TopSites> top_sites_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeHistoryClient);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_CHROME_HISTORY_CLIENT_H_