Host-side implementation of ARC Intent handler

components/arc/common/intent_helper.mojom

+// 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 arc;
+
+// Handles intents from ARC in Chrome.
+interface IntentHelperHost {
+  // Opens the url with Chrome for Chrome OS.
+  OnOpenUrl@0(string url);
+};
+
+// Sends intents to ARC on behalf of Chrome.
+interface IntentHelperInstance {
+  // Establishes full-duplex communication with the host.
+  Init@0(IntentHelperHost host_ptr);
+
+  // TODO(yusukes): Merge settings.mojom into intent_helper.mojom.
+};