[MD settings] disable clear browsing data while it is running

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/memory/ptr_util.h"
@@ skipping 196 matching lines @@
       "cr.webUIListenerCallback",
       base::StringValue("browsing-history-pref-changed"),
       base::FundamentalValue(
           profile_->GetPrefs()->GetBoolean(
               prefs::kAllowDeletingBrowserHistory)));
 }
 
 void ClearBrowsingDataHandler::HandleInitialize(const base::ListValue* args) {
   AllowJavascript();
 
+  CallJavascriptFunction(
+      "cr.webUIListenerCallback",
+      base::StringValue("clearing-browsing-data"),
+      base::FundamentalValue(!!remover_));
+
   // TODO(msramek): Simplify this using a factory.
   AddCounter(base::WrapUnique(new AutofillCounter()));
   AddCounter(base::WrapUnique(new CacheCounter()));
   AddCounter(base::WrapUnique(new DownloadsCounter()));
   AddCounter(base::WrapUnique(new HistoryCounter()));
   AddCounter(base::WrapUnique(new HostedAppsCounter()));
   AddCounter(base::WrapUnique(new PasswordsCounter()));
   AddCounter(base::WrapUnique(new MediaLicensesCounter()));
 
   OnStateChanged();
@@ skipping 58 matching lines @@
 void ClearBrowsingDataHandler::UpdateCounterText(
     std::unique_ptr<BrowsingDataCounter::Result> result) {
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("update-counter-text"),
       base::StringValue(result->source()->GetPrefName()),
       base::StringValue(GetCounterTextFromResult(result.get())));
 }
 
 }  // namespace settings