Add histograms for notices about other forms of browsing history

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

 // 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.
 
 #include "chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.h"
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 181 matching lines @@
   browsing_data_ui::ShouldShowNoticeAboutOtherFormsOfBrowsingHistory(
       sync_service_,
       WebHistoryServiceFactory::GetForProfile(Profile::FromWebUI(web_ui())),
       base::Bind(&ClearBrowsingDataHandler::UpdateHistoryNotice,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void ClearBrowsingDataHandler::UpdateHistoryNotice(bool show) {
   should_show_history_footer_ = show;
   OnStateChanged();
+
+  UMA_HISTOGRAM_BOOLEAN(
+      "History.ClearBrowsingData.HistoryNoticeShownInFooterWhenUpdated",
+      should_show_history_footer_);
 }
 
 }  // namespace settings