Remove TopSites notification in favor of Observers

chrome/browser/android/most_visited_sites.h

 // Copyright 2013 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_ANDROID_MOST_VISITED_SITES_H_
 #define CHROME_BROWSER_ANDROID_MOST_VISITED_SITES_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/profile_sync_service_observer.h"
 #include "components/history/core/browser/history_types.h"
+#include "components/history/core/browser/top_sites_observer.h"
 #include "components/suggestions/proto/suggestions.pb.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 
 namespace suggestions {
 class SuggestionsService;
 }
 
 // Provides the list of most visited sites and their thumbnails to Java.
 class MostVisitedSites : public ProfileSyncServiceObserver,
-                         public content::NotificationObserver {
+                         public history::TopSitesObserver {
  public:
   typedef base::Callback<
       void(base::android::ScopedJavaGlobalRef<jobject>* bitmap,
            base::android::ScopedJavaGlobalRef<jobject>* j_callback)>
       LookupSuccessCallback;
 
   explicit MostVisitedSites(Profile* profile);
   void Destroy(JNIEnv* env, jobject obj);
   void OnLoadingComplete(JNIEnv* env, jobject obj);
   void SetMostVisitedURLsObserver(JNIEnv* env,
                                   jobject obj,
                                   jobject j_observer,
                                   jint num_sites);
   void GetURLThumbnail(JNIEnv* env,
                        jobject obj,
                        jstring url,
                        jobject j_callback);
   void BlacklistUrl(JNIEnv* env, jobject obj, jstring j_url);
   void RecordOpenedMostVisitedItem(JNIEnv* env, jobject obj, jint index);
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) override;
-
   // ProfileSyncServiceObserver implementation.
   virtual void OnStateChanged() override;
 
   // Registers JNI methods.
   static bool Register(JNIEnv* env);
 
  private:
   // The source of the Most Visited sites.
   enum MostVisitedSource {
     TOP_SITES,
@@ skipping 31 matching lines @@
 
   // Callback from the SuggestionsServer regarding the server thumbnail lookup.
   void OnSuggestionsThumbnailAvailable(
       base::android::ScopedJavaGlobalRef<jobject>* j_callback,
       const GURL& url,
       const SkBitmap* bitmap);
 
   // Records specific UMA histogram metrics.
   void RecordUMAMetrics();
 
+  // history::TopSitesObserver implementation.
+  void TopSitesLoaded(history::TopSites* top_sites) override;
+  void TopSitesChanged(history::TopSites* top_sites) override;
+
   // The profile whose most visited sites will be queried.
   Profile* profile_;
 
   // The observer to be notified when the list of most visited sites changes.
   base::android::ScopedJavaGlobalRef<jobject> observer_;
 
   // The maximum number of most visited sites to return.
   int num_sites_;
 
   // Whether the user is in a control group for the purposes of logging.
   bool is_control_group_;
 
   // Keeps track of whether the initial NTP load has been done.
   bool initial_load_done_;
 
   // Counters for UMA metrics.
 
   // Number of tiles using a local thumbnail image for this NTP session.
   int num_local_thumbs_;
   // Number of tiles for which a server thumbnail is provided.
   int num_server_thumbs_;
   // Number of tiles for which no thumbnail is found/specified and a gray tile
   // is used as the main tile.
   int num_empty_thumbs_;
 
   // Copy of the server suggestions (if enabled). Used for logging.
   suggestions::SuggestionsProfile server_suggestions_;
 
-  content::NotificationRegistrar registrar_;
+  ScopedObserver<history::TopSites, history::TopSitesObserver> scoped_observer_;
 
   MostVisitedSource mv_source_;
 
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<MostVisitedSites> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MostVisitedSites);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_MOST_VISITED_SITES_H_