Add chrome://site-engagement WebUI.

chrome/browser/ui/webui/engagement/site_engagement_ui.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_WEBUI_ENGAGEMENT_SITE_ENGAGEMENT_UI_H_
+#define CHROME_BROWSER_UI_WEBUI_ENGAGEMENT_SITE_ENGAGEMENT_UI_H_
+
+#include "base/basictypes.h"
+#include "chrome/browser/ui/webui/engagement/site_engagement.mojom.h"
+#include "chrome/browser/ui/webui/mojo_web_ui_controller.h"
+
+// The UI for chrome://site-engagement/.
+class SiteEngagementUI
+    : public MojoWebUIController<SiteEngagementUIHandlerMojo> {
+ public:
+  explicit SiteEngagementUI(content::WebUI* web_ui);
+  ~SiteEngagementUI() override;
+
+ private:
+  // MojoWebUIController overrides:
+  void BindUIHandler(
+      mojo::InterfaceRequest<SiteEngagementUIHandlerMojo> request) override;
+
+  DISALLOW_COPY_AND_ASSIGN(SiteEngagementUI);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_ENGAGEMENT_SITE_ENGAGEMENT_UI_H_