Require Secure Context and a Feature Policy for gamepad behind flag

For privacy concerns there is a push to add feature policy and Secure
Context requirements to gamepads. We are adding these behind a flag now
so that we can more easily coordinate the rollout with other browsers.

Bug: 1099544
Change-Id: Ic64ae35d74692eaf29f618f8fdbb49cf7a143751
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2269718
Commit-Queue: James Hollyer <[email protected]>
Reviewed-by: Oliver Chang <[email protected]>
Reviewed-by: Dmitry Gozman <[email protected]>
Reviewed-by: Matt Reynolds <[email protected]>
Cr-Commit-Position: refs/heads/master@{#791991}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index feb0511..73cda43 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -1101,6 +1101,9 @@
 extern const char kRequestUnbufferedDispatchName[];
 extern const char kRequestUnbufferedDispatchDescription[];
 
+extern const char kRestrictGamepadAccessName[];
+extern const char kRestrictGamepadAccessDescription[];
+
 extern const char kRequestTabletSiteName[];
 extern const char kRequestTabletSiteDescription[];