Add shutdown notification and service refs to SyncServiceObserver.

chrome/browser/ui/webui/options/clear_browser_data_handler.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/ui/webui/options/clear_browser_data_handler.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 373 matching lines @@
 
 void ClearBrowserDataHandler::UpdateCounterText(
     std::unique_ptr<browsing_data::BrowsingDataCounter::Result> result) {
   DCHECK(AreCountersEnabled());
   web_ui()->CallJavascriptFunctionUnsafe(
       "ClearBrowserDataOverlay.updateCounter",
       base::StringValue(result->source()->GetPrefName()),
       base::StringValue(GetChromeCounterTextFromResult(result.get())));
 }
 
-void ClearBrowserDataHandler::OnStateChanged() {
+void ClearBrowserDataHandler::OnStateChanged(syncer::SyncService* sync) {
   web_ui()->CallJavascriptFunctionUnsafe(
       "ClearBrowserDataOverlay.updateSyncWarningAndHistoryFooter",
       base::FundamentalValue(sync_service_ && sync_service_->IsSyncActive()),
       base::FundamentalValue(should_show_history_notice_));
 }
 
 void ClearBrowserDataHandler::RefreshHistoryNotice() {
   browsing_data::ShouldShowNoticeAboutOtherFormsOfBrowsingHistory(
       sync_service_,
       WebHistoryServiceFactory::GetForProfile(Profile::FromWebUI(web_ui())),
@@ skipping 11 matching lines @@
         sync_service_,
         WebHistoryServiceFactory::GetForProfile(Profile::FromWebUI(web_ui())),
         chrome::GetChannel(),
         base::Bind(&ClearBrowserDataHandler::UpdateHistoryDeletionDialog,
                    weak_ptr_factory_.GetWeakPtr()));
   }
 }
 
 void ClearBrowserDataHandler::UpdateHistoryNotice(bool show) {
   should_show_history_notice_ = show;
-  OnStateChanged();
+  OnStateChanged(nullptr);

[sky, 2017/01/27 16:29:44]

This seems error prone. I recommend having OnStateChanged() and this call a
function with no args. Maybe UpdateSyncState() as other files have.

[Steven Holte, 2017/01/27 20:11:45]

Done.

 
   UMA_HISTOGRAM_BOOLEAN(
       "History.ClearBrowsingData.HistoryNoticeShownInFooterWhenUpdated",
       should_show_history_notice_);
 }
 
 void ClearBrowserDataHandler::UpdateHistoryDeletionDialog(bool show) {
   // This is used by OnBrowsingDataRemoverDone (when the deletion finishes).
   should_show_history_deletion_dialog_ = show;
 }
 
 }  // namespace options