Add chrome://site-engagement WebUI.

chrome/browser/ui/webui/engagement/site_engagement.mojom

Index: chrome/browser/ui/webui/engagement/site_engagement.mojom
diff --git a/third_party/mojo/src/mojo/public/interfaces/bindings/tests/scoping.mojom b/chrome/browser/ui/webui/engagement/site_engagement.mojom
similarity index 52%
copy from third_party/mojo/src/mojo/public/interfaces/bindings/tests/scoping.mojom
copy to chrome/browser/ui/webui/engagement/site_engagement.mojom
index 2e9edb10b4eddfca591bdf64966238b9a75fbe2f..b39db67614d7220d4c28d8190fabc174dd5bd9a6 100644
--- a/third_party/mojo/src/mojo/public/interfaces/bindings/tests/scoping.mojom
+++ b/chrome/browser/ui/webui/engagement/site_engagement.mojom
@@ -2,16 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module mojo.test;
-
-interface A {
-  GetB(B& b);
-};
-
-interface B {
-  GetC(C& c);
+struct SiteEngagementInfo {
+  string origin;
+  int32 score;
 };
 
-interface C {
-  D();
+interface SiteEngagementUIHandler {
+  GetSiteEngagementInfo() => (array<SiteEngagementInfo> info);
 };