[MD settings] explain when no usb devices are shown in site settings

chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.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/md_settings_localized_strings_provider.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/i18n/number_formatting.h"
@@ skipping 1662 matching lines @@
      IDS_SETTINGS_COOKIES_LOCAL_STORAGE_LAST_MODIFIED_LABEL},
     {"indexedDbOrigin", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_ORIGIN_LABEL},
     {"localStorageLastModified",
      IDS_SETTINGS_COOKIES_LOCAL_STORAGE_LAST_MODIFIED_LABEL},
     {"localStorageOrigin", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_ORIGIN_LABEL},
     {"localStorageSize", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_SIZE_ON_DISK_LABEL},
     {"mediaLicenseOrigin", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_ORIGIN_LABEL},
     {"mediaLicenseSize", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_SIZE_ON_DISK_LABEL},
     {"mediaLicenseLastModified",
      IDS_SETTINGS_COOKIES_LOCAL_STORAGE_LAST_MODIFIED_LABEL},
+    {"noUsbDevicesFound", IDS_SETTINGS_NO_USB_DEVICES_FOUND},
     {"serviceWorkerOrigin", IDS_SETTINGS_COOKIES_LOCAL_STORAGE_ORIGIN_LABEL},
     {"serviceWorkerScopes", IDS_SETTINGS_COOKIES_SERVICE_WORKER_SCOPES_LABEL},
     {"serviceWorkerSize",
      IDS_SETTINGS_COOKIES_LOCAL_STORAGE_SIZE_ON_DISK_LABEL},
     {"webdbDesc", IDS_SETTINGS_COOKIES_WEB_DATABASE_DESCRIPTION_LABEL},
     {"siteSettingsCategoryPageTitle", IDS_SETTINGS_SITE_SETTINGS_CATEGORY},
     {"siteSettingsCategoryAllSites", IDS_SETTINGS_SITE_SETTINGS_ALL_SITES},
     {"siteSettingsCategoryCamera", IDS_SETTINGS_SITE_SETTINGS_CAMERA},
     {"siteSettingsCameraLabel", IDS_SETTINGS_SITE_SETTINGS_CAMERA_LABEL},
     {"siteSettingsCategoryCookies", IDS_SETTINGS_SITE_SETTINGS_COOKIES},
@@ skipping 391 matching lines @@
 
 #if defined(OS_CHROMEOS)
   chromeos::network_element::AddLocalizedStrings(html_source);
 #endif
   policy_indicator::AddLocalizedStrings(html_source);
 
   html_source->SetJsonPath(kLocalizedStringsFile);
 }
 
 }  // namespace settings