Use mojo for WebappRegistry.

chrome/browser/android/webapps/webapp_registry.mojom

Index: chrome/browser/android/webapps/webapp_registry.mojom
diff --git a/chrome/browser/android/webapps/webapp_registry.mojom b/chrome/browser/android/webapps/webapp_registry.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..1331545aa3eb7710e03bf40a228efe0ac00e60e1
--- /dev/null
+++ b/chrome/browser/android/webapps/webapp_registry.mojom
@@ -0,0 +1,15 @@
+// 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.
+
+[JavaPackage="org.chromium.mojom.chrome"]
+module mojom;
+
+interface WebappRegistry {
+  // Cleans up data stored by web apps.
+  UnregisterAllWebapps() => ();
+
+  // Removes history data (last used time and URLs) stored by web apps, whilst
+  // leaving other data intact.
+  ClearWebappHistory() => ();
+};