Revert of Remove webrtc/libjingle/{xmllite,xmpp}

webrtc/libjingle/xmpp/pingtask.h

Index: webrtc/libjingle/xmpp/pingtask.h
diff --git a/webrtc/libjingle/xmpp/pingtask.h b/webrtc/libjingle/xmpp/pingtask.h
new file mode 100644
index 0000000000000000000000000000000000000000..b070a1ccf1ebbc83b5c4acd9c1b7a544098300e6
--- /dev/null
+++ b/webrtc/libjingle/xmpp/pingtask.h
@@ -0,0 +1,55 @@
+/*
+ *  Copyright 2011 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_LIBJINGLE_XMPP_PINGTASK_H_
+#define WEBRTC_LIBJINGLE_XMPP_PINGTASK_H_
+
+#include "webrtc/libjingle/xmpp/xmpptask.h"
+#include "webrtc/base/messagehandler.h"
+#include "webrtc/base/messagequeue.h"
+
+namespace buzz {
+
+// Task to periodically send pings to the server to ensure that the network
+// connection is valid, implementing XEP-0199.
+//
+// This is especially useful on cellular networks because:
+// 1. It keeps the connections alive through the cellular network's NATs or
+//    proxies.
+// 2. It detects when the server has crashed or any other case in which the
+//    connection has broken without a fin or reset packet being sent to us.
+class PingTask : public buzz::XmppTask, private rtc::MessageHandler {
+ public:
+  PingTask(buzz::XmppTaskParentInterface* parent,
+           rtc::MessageQueue* message_queue,
+           uint32_t ping_period_millis,
+           uint32_t ping_timeout_millis);
+
+  virtual bool HandleStanza(const buzz::XmlElement* stanza);
+  virtual int ProcessStart();
+
+  // Raised if there is no response to a ping within ping_timeout_millis.
+  // The task is automatically aborted after a timeout.
+  sigslot::signal0<> SignalTimeout;
+
+ private:
+  // Implementation of MessageHandler.
+  virtual void OnMessage(rtc::Message* msg);
+
+  rtc::MessageQueue* message_queue_;
+  uint32_t ping_period_millis_;
+  uint32_t ping_timeout_millis_;
+  int64_t next_ping_time_;
+  int64_t ping_response_deadline_;  // 0 if the response has been received
+};
+
+} // namespace buzz
+
+#endif  // WEBRTC_LIBJINGLE_XMPP_PINGTASK_H_