Add notifications content settings type.

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 43c1a1f8bf4babc5e518735c45fbd47e3a578aea..332e32046c2a7b70f0d5b7c4caf1a9ceca13d0c7 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -651,7 +651,11 @@ bool TabContents::ShouldDisplayFavIcon() {
 
 bool TabContents::IsContentBlocked(ContentSettingsType content_type) const {
   DCHECK(content_type != CONTENT_SETTINGS_TYPE_GEOLOCATION)
-      << "Geolocation settings handled by GeolocationContentSettingsMap";
+      << "Geolocation settings handled by ContentSettingGeolocationImageModel";
+  DCHECK(content_type != CONTENT_SETTINGS_TYPE_NOTIFICATIONS)
+      << "Notifications settings handled by "
+      << "ContentSettingsNotificationsImageModel";
+
   if (content_type == CONTENT_SETTINGS_TYPE_POPUPS)
     return blocked_popups_ != NULL;