Capabilities + Extensions + Cast Host Extension Support for Android client

remoting/android/java/src/org/chromium/chromoting/ClientExtension.java

+// Copyright 2014 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.
+
+package org.chromium.chromoting;
+
+import android.app.Activity;
+
+/**
+ * Interface to extend the Android client's functionality by providing a way to communicate with
+ * the Chromoting host.
+ */
+public interface ClientExtension {
+
+    /** Returns the capability supported by this extension, or an empty string. */
+    public String getCapability();
+
+    /**
+     * Called when the client receives an extension message from the host through JniInterface. It
+     * returns true if the message was handled appropriately, and false otherwise.
+     */
+    public boolean onExtensionMessage(String type, String data);
+
+    /**
+     * Called when an activity offers to accept an ActivityListener for its lifecycle events.
+     * This gives Extensions the option to hook into an existing Activity, get notified about
+     * changes in its state and modify its behavior. Returns the extension's activity listener,
+     * or null.
+     */
+    public ActivityLifecycleListener onActivityAcceptingListener(Activity activity);
+
+}