[GCM] Start GCMChannelStatusSyncer when GCM is disabled

components/gcm_driver/gcm_driver_desktop.cc

Index: components/gcm_driver/gcm_driver_desktop.cc
diff --git a/components/gcm_driver/gcm_driver_desktop.cc b/components/gcm_driver/gcm_driver_desktop.cc
index ca1f45f8ffd3495d6cc1eb15002def2288901268..463c0620cc6f86d563cd974ccdd97f0eef77949a 100644
--- a/components/gcm_driver/gcm_driver_desktop.cc
+++ b/components/gcm_driver/gcm_driver_desktop.cc
@@ -427,8 +427,10 @@ void GCMDriverDesktop::RemoveAppHandler(const std::string& app_id) {
   GCMDriver::RemoveAppHandler(app_id);
 
   // Stops the GCM service when no app intends to consume it.
-  if (app_handlers().empty())
+  if (app_handlers().empty()) {
     Stop();
+    gcm_channel_status_syncer_->Stop();
+  }
 }
 
 void GCMDriverDesktop::AddConnectionObserver(GCMConnectionObserver* observer) {
@@ -467,8 +469,6 @@ void GCMDriverDesktop::Stop() {
   if (!gcm_started_)
     return;
 
-  gcm_channel_status_syncer_->Stop();
-
   RemoveCachedData();
 
   io_thread_->PostTask(
@@ -641,8 +641,14 @@ GCMClient::Result GCMDriverDesktop::EnsureStarted() {
   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())