[OpenXR] Add build flag and feature flag.

Part 1/5 from splitting crrev.com/c/1629016.

Bug: 974396
Change-Id: Ic882049650b274cdd8d83315d39e5d80b9ebcb79
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1661272
Reviewed-by: Bill Orr <[email protected]>
Commit-Queue: Patrick To <[email protected]>
Cr-Commit-Position: refs/heads/master@{#669533}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index d017453..f7dbeeb6 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -2047,6 +2047,11 @@
 extern const char kWindowsMixedRealityDescription[];
 #endif  // ENABLE_WINDOWS_MR
 
+#if BUILDFLAG(ENABLE_OPENXR)
+extern const char kOpenXRName[];
+extern const char kOpenXRDescription[];
+#endif  // ENABLE_OPENXR
+
 #if BUILDFLAG(ENABLE_ISOLATED_XR_SERVICE)
 extern const char kXRSandboxName[];
 extern const char kXRSandboxDescription[];