[GCM] Add app handler support for connection events

components/gcm_driver/gcm_app_handler.h

 // Copyright (c) 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.
 
 #ifndef COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_
 #define COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "components/gcm_driver/gcm_client.h"
 
 namespace gcm {
 
 // Defines the interface to provide handling and event routing logic for a given
 // app.
 class GCMAppHandler {
  public:
-  GCMAppHandler() {}
-  virtual ~GCMAppHandler() {}
+  GCMAppHandler();
+  virtual ~GCMAppHandler();
 
   // Called to do all the cleanup when GCM is shutting down.
   // In the case that multiple apps share the same app handler, it should be
   // make safe for ShutdownHandler to be called multiple times.
   virtual void ShutdownHandler() = 0;
 
   // Called when a GCM message has been received.
   virtual void OnMessage(const std::string& app_id,
                          const GCMClient::IncomingMessage& message) = 0;
 
   // Called when some GCM messages have been deleted from the server.
   virtual void OnMessagesDeleted(const std::string& app_id) = 0;
 
   // Called when a GCM message failed to be delivered.
   virtual void OnSendError(
       const std::string& app_id,
       const GCMClient::SendErrorDetails& send_error_details) = 0;
+
+  // Called when a new connection is established and a successful handshake
+  // has been performed. Note that |ip_endpoint| is only set if available for
+  // the current platform.
+  // Default implementation does nothing.
+  virtual void OnConnected(const net::IPEndPoint& ip_endpoint);
+
+  // Called when the connection is interrupted.
+  // Default implementation does nothing.
+  virtual void OnDisconnected();
 };
 
 }  // namespace gcm
 
 #endif  // COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_