Add chrome://flag to enable the Stale Previews timestamp

chrome/browser/flag_descriptions.cc

 // Copyright 2017 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/flag_descriptions.h"
 
 namespace flag_descriptions {
 
 const char kBrowserSideNavigationName[] = "Enable browser side navigation";
 
@@ skipping 1177 matching lines @@
     "Use a carrier-specific Data Reduction Proxy for testing.";
 
 const char kEnableDataReductionProxySavingsPromoName[] =
     "Data Saver 1 MB Savings Promo";
 
 const char kEnableDataReductionProxySavingsPromoDescription[] =
     "Enable a Data Saver promo for 1 MB of savings. If Data Saver has "
     "already saved 1 MB of data, then the promo will not be shown. Data "
     "Saver must be enabled for the promo to be shown.";
 
+const char kEnableStalePreviewsName[] = "Stale Previews Timestamp";
+
+const char kEnableStalePreviewsDescription[] =
+    "Enable showing a timestamp that says how old a Preview is on the Previews "
+    "infobar.";
+
 #if defined(OS_ANDROID)
 
 const char kEnableDataReductionProxyMainMenuName[] =
     "Enable Data Saver main menu footer";
 
 const char kEnableDataReductionProxyMainMenuDescription[] =
     "Enables the Data Saver footer in the main menu";
 
 const char kEnableDataReductionProxySiteBreakdownName[] =
     "Data Saver Site Breakdown";
@@ skipping 2025 matching lines @@
     "in non-sticky mode (do not change work area in non-sticky mode).";
 
 const char kUiDevToolsName[] = "Enable native UI inspection";
 const char kUiDevToolsDescription[] =
     "Enables inspection of native UI elements. For local inspection use "
     "chrome://inspect#other";
 
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace flag_descriptions