[GCM] Start GCMChannelStatusSyncer when GCM is disabled

components/gcm_driver/gcm_driver_desktop.cc

 // 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.
 
 #include "components/gcm_driver/gcm_driver_desktop.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 623 matching lines @@
                  base::Unretained(io_worker_.get()),
                  account_tokens));
 }
 
 GCMClient::Result GCMDriverDesktop::EnsureStarted() {
   DCHECK(ui_thread_->RunsTasksOnCurrentThread());
 
   if (gcm_started_)
     return GCMClient::SUCCESS;
 
-  if (!gcm_enabled_)
+  if (!gcm_enabled_) {
+    // Poll for channel status in order to find out when it is re-enabled when
+    // GCM is currently disabled.
+    if (GCMDriver::IsAllowedForAllUsers())
+      gcm_channel_status_syncer_->EnsureStarted();
+
     return GCMClient::GCM_DISABLED;
+  }
 
   // Have any app requested the service?
   if (app_handlers().empty())
     return GCMClient::UNKNOWN_ERROR;
 
   // TODO(jianli): To be removed when sign-in enforcement is dropped.
   if (!signed_in_ && !GCMDriver::IsAllowedForAllUsers())
     return GCMClient::NOT_SIGNED_IN;
 
   DCHECK(!delayed_task_controller_);
@@ skipping 114 matching lines @@
 
   // Normally request_gcm_statistics_callback_ would not be null.
   if (!request_gcm_statistics_callback_.is_null())
     request_gcm_statistics_callback_.Run(stats);
   else
     LOG(WARNING) << "request_gcm_statistics_callback_ is NULL.";
 }
 
 }  // namespace gcm