Remove TopSites notification in favor of Observers

chrome/browser/ui/webui/ntp/most_visited_handler.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/ui/webui/ntp/most_visited_handler.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/md5.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
 #include "base/values.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/thumbnails/thumbnail_list_source.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_utils.h"
 #include "chrome/browser/ui/webui/favicon_source.h"
 #include "chrome/browser/ui/webui/ntp/new_tab_ui.h"
 #include "chrome/browser/ui/webui/ntp/ntp_stats.h"
 #include "chrome/browser/ui/webui/ntp/thumbnail_source.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "components/history/core/browser/page_usage_data.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/navigation_entry.h"
-#include "content/public/browser/notification_source.h"
 #include "content/public/browser/url_data_source.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
 #include "url/gurl.h"
 
 using base::UserMetricsAction;
 
 MostVisitedHandler::MostVisitedHandler()
-    : got_first_most_visited_request_(false),
+    : scoped_observer_(this),
+      got_first_most_visited_request_(false),
       most_visited_viewed_(false),
       user_action_logged_(false),
       weak_ptr_factory_(this) {
 }
 
 MostVisitedHandler::~MostVisitedHandler() {
   if (!user_action_logged_ && most_visited_viewed_) {
     const GURL ntp_url = GURL(chrome::kChromeUINewTabURL);
     int action_id = NTP_FOLLOW_ACTION_OTHER;
     content::NavigationEntry* entry =
@@ skipping 14 matching lines @@
   content::URLDataSource::Add(profile, new ThumbnailSource(profile, false));
   content::URLDataSource::Add(profile, new ThumbnailSource(profile, true));
 
   // Set up our sources for top-sites data.
   content::URLDataSource::Add(profile, new ThumbnailListSource(profile));
 
   // Register chrome://favicon as a data source for favicons.
   content::URLDataSource::Add(
       profile, new FaviconSource(profile, FaviconSource::FAVICON));
 
-  history::TopSites* ts = profile->GetTopSites();
-  if (ts) {
+  history::TopSites* top_sites = profile->GetTopSites();
+  if (top_sites) {
     // TopSites updates itself after a delay. This is especially noticable when
     // your profile is empty. Ask TopSites to update itself when we're about to
     // show the new tab page.
-    ts->SyncWithHistory();
+    top_sites->SyncWithHistory();
 
-    // Register for notification when TopSites changes so that we can update
-    // ourself.
-    registrar_.Add(this, chrome::NOTIFICATION_TOP_SITES_CHANGED,
-                   content::Source<history::TopSites>(ts));
+    // Register as TopSitesObserver so that we can update ourselves when the
+    // TopSites changes.
+    scoped_observer_.Add(top_sites);
   }
 
   // We pre-emptively make a fetch for the most visited pages so we have the
   // results sooner.
   StartQueryForMostVisited();
 
   web_ui()->RegisterMessageCallback("getMostVisited",
       base::Bind(&MostVisitedHandler::HandleGetMostVisited,
                  base::Unretained(this)));
 
@@ skipping 129 matching lines @@
 }
 
 void MostVisitedHandler::OnMostVisitedUrlsAvailable(
     const history::MostVisitedURLList& data) {
   SetPagesValueFromTopSites(data);
   if (got_first_most_visited_request_) {
     SendPagesValue();
   }
 }
 
-void MostVisitedHandler::Observe(int type,
-                                 const content::NotificationSource& source,
-                                 const content::NotificationDetails& details) {
-  DCHECK_EQ(type, chrome::NOTIFICATION_TOP_SITES_CHANGED);
+void MostVisitedHandler::TopSitesLoaded(history::TopSites* top_sites) {
+}
 
+void MostVisitedHandler::TopSitesChanged(history::TopSites* top_sites) {
   // Most visited urls changed, query again.
   StartQueryForMostVisited();
 }
 
 void MostVisitedHandler::BlacklistUrl(const GURL& url) {
   history::TopSites* ts = Profile::FromWebUI(web_ui())->GetTopSites();
   if (ts)
     ts->AddBlacklistedURL(url);
   content::RecordAction(UserMetricsAction("MostVisited_UrlBlacklisted"));
 }
 
 std::string MostVisitedHandler::GetDictionaryKeyForUrl(const std::string& url) {
   return base::MD5String(url);
 }
 
 // static
 void MostVisitedHandler::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterDictionaryPref(
       prefs::kNtpMostVisitedURLsBlacklist,
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
 }