Add flag to enable WebXR, changed runtime feature name from WebVR2

Bug: 670510
Change-Id: I4f135d13ac44ac6214b74eb03eb7734d6786a737
Reviewed-on: https://chromium-review.googlesource.com/817976
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: David Dorwin <[email protected]>
Commit-Queue: Brandon Jones <[email protected]>
Cr-Commit-Position: refs/heads/master@{#523231}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 56c1f2f..8f8cb914 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -992,6 +992,9 @@
 extern const char kWebVrExperimentalRenderingName[];
 extern const char kWebVrExperimentalRenderingDescription[];
 
+extern const char kWebXrName[];
+extern const char kWebXrDescription[];
+
 extern const char kWifiCredentialSyncName[];
 extern const char kWifiCredentialSyncDescription[];