Display: set color_depth and depth_per_component value based on kEnableHDROutput

ui/display/display_switches.cc

Index: ui/display/display_switches.cc
diff --git a/ui/display/display_switches.cc b/ui/display/display_switches.cc
index 945635dfe99a884cf7a0bee8196c505cd130806c..891715618a10a6ddb36dbe05589983730832c8fc 100644
--- a/ui/display/display_switches.cc
+++ b/ui/display/display_switches.cc
@@ -38,6 +38,9 @@ const char kScreenConfig[] = "screen-config";
 // This is for debugging on linux desktop.
 const char kUseFirstDisplayAsInternal[] = "use-first-display-as-internal";
 
+// Use an fp16 scRGB swap chain compatible with HDR output.
+const char kEnableHDR[] = "enable-hdr";
+
 #if defined(OS_CHROMEOS)
 const char kDisableDisplayColorCalibration[] =
     "disable-display-color-calibration";