content: convert zoom notifications to observer usage

chrome/browser/profiles/profile_impl.cc

Index: chrome/browser/profiles/profile_impl.cc
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index 695e92e9f2c79145d89e436bcff37e1636172aaf..79aa120a202e26f8db16a510be1f713ffd77fe36 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -568,8 +568,9 @@ void ProfileImpl::InitHostZoomMap() {
     }
   }
 
-  registrar_.Add(this, content::NOTIFICATION_ZOOM_LEVEL_CHANGED,
-                 content::Source<HostZoomMap>(host_zoom_map));
+  host_zoom_map->AddZoomLevelChangedCallback(
+      base::Bind(&ProfileImpl::OnZoomLevelChanged,
+                 base::Unretained(this)));
 }
 
 FilePath ProfileImpl::last_selected_directory() {
@@ -583,6 +584,10 @@ void ProfileImpl::set_last_selected_directory(const FilePath& path) {
 ProfileImpl::~ProfileImpl() {
   MaybeSendDestroyedNotification();
 
+  HostZoomMap::GetForBrowserContext(this)->RemoveZoomLevelChangedCallback(
+      base::Bind(&ProfileImpl::OnZoomLevelChanged,
+                 base::Unretained(this)));
+
   bool prefs_loaded = prefs_->GetInitializationStatus() !=
       PrefService::INITIALIZATION_STATUS_WAITING;
 
@@ -914,6 +919,21 @@ history::TopSites* ProfileImpl::GetTopSitesWithoutCreating() {
   return top_sites_;
 }
 
+void ProfileImpl::OnZoomLevelChanged(const std::string& host) {
+  if (host.empty())
+    return;
+  HostZoomMap* host_zoom_map = HostZoomMap::GetForBrowserContext(this);
+  double level = host_zoom_map->GetZoomLevel(host);
+  DictionaryPrefUpdate update(prefs_.get(), prefs::kPerHostZoomLevels);
+  DictionaryValue* host_zoom_dictionary = update.Get();
+  if (level == host_zoom_map->GetDefaultZoomLevel()) {
+    host_zoom_dictionary->RemoveWithoutPathExpansion(host, NULL);
+  } else {
+    host_zoom_dictionary->SetWithoutPathExpansion(
+        host, Value::CreateDoubleValue(level));
+  }
+}
+
 void ProfileImpl::Observe(int type,
                           const content::NotificationSource& source,
                           const content::NotificationDetails& details) {
@@ -924,23 +944,6 @@ void ProfileImpl::Observe(int type,
       registrar_.Remove(this, chrome::NOTIFICATION_BOOKMARK_MODEL_LOADED,
                         content::Source<Profile>(this));
       break;
-    case content::NOTIFICATION_ZOOM_LEVEL_CHANGED: {
-      const std::string& host =
-          *(content::Details<const std::string>(details).ptr());
-      if (!host.empty()) {
-        HostZoomMap* host_zoom_map = HostZoomMap::GetForBrowserContext(this);
-        double level = host_zoom_map->GetZoomLevel(host);
-        DictionaryPrefUpdate update(prefs_.get(), prefs::kPerHostZoomLevels);
-        DictionaryValue* host_zoom_dictionary = update.Get();
-        if (level == host_zoom_map->GetDefaultZoomLevel()) {
-          host_zoom_dictionary->RemoveWithoutPathExpansion(host, NULL);
-        } else {
-          host_zoom_dictionary->SetWithoutPathExpansion(
-              host, Value::CreateDoubleValue(level));
-        }
-      }
-      break;
-    }
     default:
       NOTREACHED();
   }