ui/display: add flag to enable use of monitor's color space info

This CL adds a new flag to control if the monitor's provided color
space info is actually propagated at the DisplayManager level, and
also surfaces this flag in chrome://flags. The flag is disabled by
default and the chrome://flags entry allows for enabling it. This
flag will help debug the possibly related issue 779311.

Bug: 771345, 779311
Change-Id: I6df69c5fb9ab9954e9ff9f4fc04fe0616594315c
Reviewed-on: https://chromium-review.googlesource.com/754593
Reviewed-by: Xiaoqian Dai <[email protected]>
Reviewed-by: Stéphane Marchesin <[email protected]>
Commit-Queue: Miguel Casas <[email protected]>
Cr-Commit-Position: refs/heads/master@{#514398}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index abe2b4c..eb053767 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -1622,6 +1622,9 @@
 extern const char kEnableMashDescription[];
 extern const char kEnableMusDescription[];
 
+extern const char kUseMonitorColorSpaceName[];
+extern const char kUseMonitorColorSpaceDescription[];
+
 extern const char kVideoPlayerChromecastSupportName[];
 extern const char kVideoPlayerChromecastSupportDescription[];