MD Settings: Update some Settings handlers to use new JS lifecycle management.

chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.h

 // Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_SETTINGS_SETTINGS_CLEAR_BROWSING_DATA_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_SETTINGS_CLEAR_BROWSING_DATA_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
+#include "base/scoped_observer.h"
 #include "chrome/browser/browsing_data/browsing_data_remover.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
 #include "components/browser_sync/browser/profile_sync_service.h"
 #include "components/prefs/pref_member.h"
 
 namespace base {
 class ListValue;
 }
 
@@ skipping 37 matching lines @@
   // Finds out whether we should show notice about other forms of history stored
   // in user's account.
   void RefreshHistoryNotice();
 
   // Called as an asynchronous response to |RefreshHistoryNotice()|. Shows or
   // hides the footer about other forms of history stored in user's account.
   void UpdateHistoryNotice(bool show);
 
   // ProfileSyncService to observe sync state changes.
   ProfileSyncService* sync_service_;
+  ScopedObserver<ProfileSyncService, sync_driver::SyncServiceObserver>
+      sync_service_observer_;
 
   // If non-null it means removal is in progress.
   BrowsingDataRemover* remover_;
 
   // The WebUI callback ID of the last performClearBrowserData request. There
   // can only be one such request in-flight.
   std::string webui_callback_id_;
 
   // Keeps track of whether clearing LSO data is supported.
   BooleanPrefMember clear_plugin_lso_data_enabled_;
@@ skipping 12 matching lines @@
 
   // A weak pointer factory for asynchronous calls referencing this class.
   base::WeakPtrFactory<ClearBrowsingDataHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ClearBrowsingDataHandler);
 };
 
 }  // namespace settings
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_SETTINGS_CLEAR_BROWSING_DATA_HANDLER_H_