Change ShouldShowNoticeAboutOtherFormsOfBrowsingHistory to be asynchronous.

components/browsing_data_ui/history_notice_utils.h

 // Copyright 2016 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.
 
 #ifndef COMPONENTS_BROWSING_DATA_UI_HISTORY_NOTICE_UTILS_H_
 #define COMPONENTS_BROWSING_DATA_UI_HISTORY_NOTICE_UTILS_H_
 
+class Callback;
 class ProfileSyncService;
 
 namespace history {
 class WebHistoryService;
 }
 
 namespace browsing_data_ui {
 
 // Whether the Clear Browsing Data UI should show a notice about the existence
-// of other forms of browsing history stored in user's account.
-bool ShouldShowNoticeAboutOtherFormsOfBrowsingHistory(
+// of other forms of browsing history stored in user's account. The response
+// is returned in a |callback|.
+void ShouldShowNoticeAboutOtherFormsOfBrowsingHistory(
     const ProfileSyncService* sync_service,
-    const history::WebHistoryService* history_service);
+    const history::WebHistoryService* history_service,
+    base::Callback<void(bool)> callback);
 
 }  // namespace browsing_data_ui
 
 #endif  // COMPONENTS_BROWSING_DATA_UI_HISTORY_NOTICE_UTILS_H_