Add a flag for Windows Mixed Reality support

Bug: 924324
Change-Id: Iba37d03e0a6e8d8f20115d0a22fbf0318227af68
Reviewed-on: https://chromium-review.googlesource.com/c/1428096
Commit-Queue: Bill Orr <[email protected]>
Reviewed-by: David Dorwin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#625048}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 413e267e..bd11f66d 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -2239,6 +2239,11 @@
 extern const char kOpenVRDescription[];
 #endif  // ENABLE_OPENVR
 
+#if BUILDFLAG(ENABLE_WINDOWS_MR)
+extern const char kWindowsMixedRealityName[];
+extern const char kWindowsMixedRealityDescription[];
+#endif  // ENABLE_WINDOWS_MR
+
 #if BUILDFLAG(ENABLE_ISOLATED_XR_SERVICE)
 extern const char kXRSandboxName[];
 extern const char kXRSandboxDescription[];