Remove unnecessary promo_type_ field from notification_promo.h/.cc.

ios/chrome/browser/ui/ntp/notification_promo_whats_new.mm

 // Copyright (c) 2014 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.
 
 #import "ios/chrome/browser/ui/ntp/notification_promo_whats_new.h"
 
 #include <stdint.h>
 #include <algorithm>
 #include <memory>
 #include <vector>
@@ skipping 77 matching lines @@
         InjectFakePromo("4", "IDS_IOS_MOVE_TO_DOCK_TIP", "url", "",
                         "https://support.google.com/chrome/?p=iphone_dock",
                         "MoveToDockTipPromo", "logoWithRoundedRectangle");
         break;
       default:
         NOTREACHED();
         break;
     }
   }
 
-  notification_promo_.InitFromPrefs(
-      ios::NotificationPromo::MOBILE_NTP_WHATS_NEW_PROMO);
+  notification_promo_.InitFromPrefs();
   return InitFromNotificationPromo();
 }
 
 bool NotificationPromoWhatsNew::ClearAndInitFromJson(
     const base::DictionaryValue& json) {
   // This clears away old promos.
   notification_promo_.MigrateUserPrefs(local_state_);
 
-  notification_promo_.InitFromJson(
-      json, ios::NotificationPromo::MOBILE_NTP_WHATS_NEW_PROMO);
+  notification_promo_.InitFromJson(json);
   return InitFromNotificationPromo();
 }
 
 bool NotificationPromoWhatsNew::CanShow() const {
   if (!valid_ || !notification_promo_.CanShow()) {
     return false;
   }
 
   // Check optional restrictions.
 
@@ skipping 149 matching lines @@
       "  \"max_seconds\":259200,"
       "  \"promo_id\":$7"
       "}";
   std::string promo_json_filled_in =
       base::ReplaceStringPlaceholders(promo_json, replacements, NULL);
 
   std::unique_ptr<base::Value> value(
       base::JSONReader::Read(promo_json_filled_in));
   base::DictionaryValue* dict = NULL;
   if (value->GetAsDictionary(&dict)) {
-    notification_promo_.InitFromJson(
-        *dict, ios::NotificationPromo::MOBILE_NTP_WHATS_NEW_PROMO);
+    notification_promo_.InitFromJson(*dict);
   }
 }