[GCM] Remove GCMDriver::Purge and GCMClient::CheckOut

components/gcm_driver/gcm_client_impl.cc

Index: components/gcm_driver/gcm_client_impl.cc
diff --git a/components/gcm_driver/gcm_client_impl.cc b/components/gcm_driver/gcm_client_impl.cc
index d320df553eab3ec1121c04fd5232bd0e43fdff9b..281395dd51f050bf914d889186528e905a2c0a11 100644
--- a/components/gcm_driver/gcm_client_impl.cc
+++ b/components/gcm_driver/gcm_client_impl.cc
@@ -616,12 +616,6 @@ void GCMClientImpl::Stop() {
   gcm_store_->Close();
 }
 
-void GCMClientImpl::CheckOut() {
-  Stop();
-  gcm_store_->Destroy(base::Bind(&GCMClientImpl::OnGCMStoreDestroyed,
-                                 weak_ptr_factory_.GetWeakPtr()));
-}
-
 void GCMClientImpl::Register(const std::string& app_id,
                              const std::vector<std::string>& sender_ids) {
   DCHECK_EQ(state_, READY);