arc-bridge: Move most methods to Mojo interfaces

components/arc/common/settings.mojom

+// 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.
+
+module arc;
+
+interface SettingsInstance {
+  // Send an Android broadcast message to the Android package and class
+  // specified.  Data can be sent as extras by including a JSON map string which
+  // will be automatically converted to a bundle accessible by the receiver.
+  //
+  // Note: Broadcasts can only be sent to whitelisted packages.  Packages can be
+  // added to the whitelist in ArcBridgeService.java in the Android source.
+  SendBroadcast(string action,
+                string package,
+                string cls,
+                string extras);
+};
+