[remoting android] Implement HostService.

remoting/android/host/src/org/chromium/chromoting/host/HostService.java

Index: remoting/android/host/src/org/chromium/chromoting/host/HostService.java
diff --git a/remoting/android/host/src/org/chromium/chromoting/host/HostService.java b/remoting/android/host/src/org/chromium/chromoting/host/HostService.java
new file mode 100644
index 0000000000000000000000000000000000000000..3fdf76c23a7ea8727221fafdbc7342a6fada8386
--- /dev/null
+++ b/remoting/android/host/src/org/chromium/chromoting/host/HostService.java
@@ -0,0 +1,113 @@
+// 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.
+
+package org.chromium.chromoting.host;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.Binder;
+import android.os.IBinder;
+
+import org.chromium.chromoting.host.jni.Host;
+import org.chromium.chromoting.host.jni.It2MeHostObserver;
+
+/**
+ * This class runs the host as a background service, and maintains host state across multiple
+ * Activity lifecycles. It keeps track of the host state (and any It2Me access-code) and allows
+ * a client Activity to access this state on binding to this service.
+ */
+public class HostService extends Service implements It2MeHostObserver {
+    private class BinderImpl extends Binder {
+        private HostService getService() {
+            return HostService.this;
+        }
+    }
+
+    private Host mHost;
+
+    // Host state.
+    private It2MeHostObserver.State mState = It2MeHostObserver.State.DISCONNECTED;
+    private String mAccessCode;
+    private int mLifetimeSeconds;
+
+    // Observer allowing a client to receive notifications from the service. This is set when a
+    // client binds to this service, and unset when the client is unbound. It is assumed that only
+    // 1 client may be bound at any given time.
+    private It2MeHostObserver mObserver;
+
+    /** Allows access to the HostService from the returned IBinder object. */
+    public static HostService getFromIBinder(IBinder binder) {
+        return ((BinderImpl) binder).getService();
+    }
+
+    /**
+     * Sets the observer. Called by the client after binding to this service. This will immediately
+     * trigger simulated callbacks to reflect the current state. */
+    public void setObserver(It2MeHostObserver observer) {
+        mObserver = observer;
+        if (mState == It2MeHostObserver.State.RECEIVED_ACCESS_CODE) {
+            // TODO(lambroslambrou): Provide the expected expiry time of the access-code, instead
+            // of passing on the received duration here.
+            observer.onAccessCodeReceived(mAccessCode, mLifetimeSeconds);
+        }
+        observer.onStateChanged(mState, "");
+    }
+
+    /** Begins a client It2Me session. */
+    public void connect(String userName, String authToken) {
+        mHost.connect(userName, authToken, this);
+    }
+
+    /** Disconnects from any It2Me session. */
+    public void disconnect() {
+        mHost.disconnect();
+    }
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        mHost = new Host();
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        mHost.destroy();
+        mHost = null;
+    }
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        return START_STICKY;
+    }
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return new BinderImpl();
+    }
+
+    @Override
+    public boolean onUnbind(Intent intent) {
+        super.onUnbind(intent);
+        mObserver = null;
+        return false;
+    }
+
+    @Override
+    public void onAccessCodeReceived(String accessCode, int lifetimeSeconds) {
+        mAccessCode = accessCode;
+        mLifetimeSeconds = lifetimeSeconds;
+        if (mObserver != null) {
+            mObserver.onAccessCodeReceived(accessCode, lifetimeSeconds);
+        }
+    }
+
+    @Override
+    public void onStateChanged(State state, String errorMessage) {
+        mState = state;
+        if (mObserver != null) {
+            mObserver.onStateChanged(state, errorMessage);
+        }
+    }
+}