Add --enable-hdr to about:flags

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 63877eb6febaef5cfb98be3b192b88071265d96a..201bdf307a3f7c0c883aa7d895c6ee3225390f84 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -940,6 +940,11 @@ 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.";