Remove TopSites notification in favor of Observers

chrome/browser/ui/webui/ntp/suggestions_page_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/suggestions_page_handler.h"
 
 #include <math.h>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/md5.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string16.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/ui/webui/favicon_source.h"
 #include "chrome/browser/ui/webui/ntp/ntp_stats.h"
 #include "chrome/browser/ui/webui/ntp/suggestions_combiner.h"
 #include "chrome/browser/ui/webui/ntp/suggestions_source_top_sites.h"
 #include "chrome/browser/ui/webui/ntp/thumbnail_source.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 "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
 using base::UserMetricsAction;
 
 SuggestionsHandler::SuggestionsHandler()
-    : got_first_suggestions_request_(false),
+    : scoped_observer_(this),
+      got_first_suggestions_request_(false),
       suggestions_viewed_(false),
       user_action_logged_(false) {
 }
 
 SuggestionsHandler::~SuggestionsHandler() {
   if (!user_action_logged_ && suggestions_viewed_) {
     const GURL ntp_url = GURL(chrome::kChromeUINewTabURL);
     int action_id = NTP_FOLLOW_ACTION_OTHER;
     content::NavigationEntry* entry =
         web_ui()->GetWebContents()->GetController().GetLastCommittedEntry();
@@ skipping 16 matching lines @@
 
   // TODO(georgey) change the source of the web-sites to provide our data.
   // Initial commit uses top sites as a data source.
   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.
     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>(top_sites));
+    // Register as TopSitesObserver so that we can update ourselves when the
+    // TopSites changes.
+    scoped_observer_.Add(top_sites);
   }
 
   // Setup the suggestions sources.
   SuggestionsCombiner* combiner = new SuggestionsCombiner(this, profile);
   combiner->AddSource(new SuggestionsSourceTopSites());
   suggestions_combiner_.reset(combiner);
 
   // We pre-emptively make a fetch for suggestions so we have the results
   // sooner.
   suggestions_combiner_->FetchItems(profile);
@@ skipping 75 matching lines @@
                             NUM_NTP_FOLLOW_ACTIONS);
   suggestions_viewed_ = true;
   user_action_logged_ = true;
 }
 
 void SuggestionsHandler::HandleSuggestedSitesSelected(
     const base::ListValue* args) {
   suggestions_viewed_ = true;
 }
 
-void SuggestionsHandler::Observe(int type,
-                                 const content::NotificationSource& source,
-                                 const content::NotificationDetails& details) {
-  DCHECK_EQ(type, chrome::NOTIFICATION_TOP_SITES_CHANGED);
+void SuggestionsHandler::TopSitesLoaded(history::TopSites* top_sites) {
+}
 
+void SuggestionsHandler::TopSitesChanged(history::TopSites* top_sites) {
   // Suggestions urls changed, query again.
   suggestions_combiner_->FetchItems(Profile::FromWebUI(web_ui()));
 }
 
 void SuggestionsHandler::BlacklistURL(const GURL& url) {
   // TODO(georgey) blacklist an URL.
 }
 
 std::string SuggestionsHandler::GetDictionaryKeyForURL(const std::string& url) {
   return base::MD5String(url);
 }
 
 // static
 void SuggestionsHandler::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   // TODO(georgey) add user preferences (such as own blacklist) as needed.
 }