Plumb site engagement to the renderer process.

third_party/WebKit/public/platform/site_engagement.mojom

Index: third_party/WebKit/public/platform/site_engagement.mojom
diff --git a/third_party/WebKit/public/platform/site_engagement.mojom b/third_party/WebKit/public/platform/site_engagement.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..f35f0ce373bf167d4662462cfca2f0bf666ce677
--- /dev/null
+++ b/third_party/WebKit/public/platform/site_engagement.mojom
@@ -0,0 +1,21 @@
+// Copyright 2016 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.
+
+module blink.mojom;
+
+import "url/mojo/origin.mojom";
+
+enum EngagementLevel {
+  NONE,
+  MINIMAL,
+  LOW,
+  MEDIUM,
+  HIGH,
+  MAX,
+};
+
+interface EngagementClient {
+  // The browser tells the renderer the engagement level of the provided origin.
+  SetEngagementLevel(url.mojom.Origin origin, EngagementLevel level);
+};