Added accessor for the ukm service to the browser process singleton

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 0b51f69d261cc8670866b76b9b5c966102c36259..f69f9b8ed06aa83f9aa8bc1c7dd49810de011351 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -541,6 +541,11 @@ rappor::RapporServiceImpl* BrowserProcessImpl::rappor_service() {
   return GetMetricsServicesManager()->GetRapporServiceImpl();
 }
 
+ukm::UkmService* BrowserProcessImpl::ukm_service() {
+  DCHECK(CalledOnValidThread());
+  return GetMetricsServicesManager()->GetUkmService();
+}
+
 IOThread* BrowserProcessImpl::io_thread() {
   DCHECK(CalledOnValidThread());
   DCHECK(io_thread_.get());