Add --enable-hdr to about:flags

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 {
 
 //  Material Design version of chrome://bookmarks
 
@@ skipping 922 matching lines @@
 const char kBootAnimationDescription[] =
     "Wallpaper boot animation (except for OOBE case).";
 
 #endif  // defined(OS_CHROMEOS)
 
 const char kAcceleratedVideoDecodeName[] = "Hardware-accelerated video decode";
 
 const char kAcceleratedVideoDecodeDescription[] =
     "Hardware-accelerated video decode where available.";
 
+const char kEnableHDRName[] = "HDR mode";
+
+const char kEnableHDRDescription[] =
+    "Enables HDR support on compatible displays.";
+
 const char kCloudImport[] = "Cloud Import";
 
 const char kCloudImportDescription[] = "Allows the cloud-import feature.";
 
 const char kRequestTabletSiteName[] =
     "Request tablet site option in the settings menu";
 
 const char kRequestTabletSiteDescription[] =
     "Allows the user to request tablet site. Web content is often optimized "
     "for tablet devices. When this option is selected the user agent string "
@@ skipping 1930 matching lines @@
 const char kEnableEhvInputName[] =
     "Emoji, handwriting and voice input on opt-in IME menu";
 
 const char kEnableEhvInputDescription[] =
     "Enable access to emoji, handwriting and voice input form opt-in IME "
     "menu.";
 
 #endif  // #if defined(OS_CHROMEOS)
 
 }  // namespace flag_descriptions