Add empty list indicator for Physical Web WebUI

ios/chrome/browser/ui/webui/physical_web_ui.cc

 // 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.
 
 #include "ios/chrome/browser/ui/webui/physical_web_ui.h"
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/user_metrics.h"
 #include "components/grit/components_resources.h"
@@ skipping 10 matching lines @@
 
 namespace {
 
 web::WebUIIOSDataSource* CreatePhysicalWebUIDataSource() {
   web::WebUIIOSDataSource* html_source =
       web::WebUIIOSDataSource::Create(kChromeUIPhysicalWebHost);
 
   // Localized and data strings.
   html_source->AddLocalizedString(physical_web_ui::kTitle,
                                   IDS_PHYSICAL_WEB_UI_TITLE);
-
+  html_source->AddLocalizedString(physical_web_ui::kEmptyMessage,
+                                  IDS_PHYSICAL_WEB_UI_EMPTY_MESSAGE);
   html_source->SetJsonPath("strings.js");
   html_source->AddResourcePath(physical_web_ui::kPhysicalWebJS,
                                IDR_PHYSICAL_WEB_UI_JS);
   html_source->AddResourcePath(physical_web_ui::kPhysicalWebCSS,
                                IDR_PHYSICAL_WEB_UI_CSS);
   html_source->SetDefaultResource(IDR_PHYSICAL_WEB_UI_HTML);
   return html_source;
 }
 
 // Implements all MessageHandler core functionality.  This is extends the
@@ skipping 57 matching lines @@
     : web::WebUIIOSController(web_ui) {
   web_ui->AddMessageHandler(base::MakeUnique<PhysicalWebDOMHandler>());
 
   web::WebUIIOSDataSource::Add(ios::ChromeBrowserState::FromWebUIIOS(web_ui),
                                CreatePhysicalWebUIDataSource());
 
   base::RecordAction(base::UserMetricsAction("PhysicalWeb.WebUI.Open"));
 }
 
 PhysicalWebUI::~PhysicalWebUI() {}