use push messaging in cache invalidation xmpp channel

chrome/browser/sync/notifier/chrome_system_resources.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/sync/notifier/chrome_system_resources.h"
 
 #include <cstdlib>
 #include <cstring>
 #include <string>
 
@@ skipping 212 matching lines @@
 
 void ChromeNetwork::UpdatePacketHandler(
     CacheInvalidationPacketHandler* packet_handler) {
   packet_handler_ = packet_handler;
   if (packet_handler_ != NULL) {
     packet_handler_->SetMessageReceiver(
         new invalidation::MessageCallback(
             base::Bind(&ChromeNetwork::HandleInboundMessage,
                        weak_factory_.GetWeakPtr())));
   }
+  packet_handler_->SendSubscriptionRequest();
 }
 
 void ChromeNetwork::HandleInboundMessage(const std::string& incoming_message) {
   if (incoming_receiver_.get()) {
     incoming_receiver_->Run(incoming_message);
   }
 }
 
 ChromeSystemResources::ChromeSystemResources(StateWriter* state_writer)
     : is_started_(false),
@@ skipping 45 matching lines @@
 
 ChromeScheduler* ChromeSystemResources::internal_scheduler() {
   return internal_scheduler_.get();
 }
 
 ChromeScheduler* ChromeSystemResources::listener_scheduler() {
   return listener_scheduler_.get();
 }
 
 }  // namespace sync_notifier