Basic UkmService implementation

chrome/browser/metrics/chrome_metrics_service_client.cc

Index: chrome/browser/metrics/chrome_metrics_service_client.cc
diff --git a/chrome/browser/metrics/chrome_metrics_service_client.cc b/chrome/browser/metrics/chrome_metrics_service_client.cc
index 670211b57d19ef15b19e96da169aba144f57889a..311760e79550834130303c90c96c0f9defc76725 100644
--- a/chrome/browser/metrics/chrome_metrics_service_client.cc
+++ b/chrome/browser/metrics/chrome_metrics_service_client.cc
@@ -70,6 +70,7 @@
 #include "components/prefs/pref_service.h"
 #include "components/sync/device_info/device_count_metrics_provider.h"
 #include "components/translate/core/browser/translate_ranker_metrics_provider.h"
+#include "components/ukm/ukm_service.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/histogram_fetcher.h"
@@ -318,6 +319,7 @@ std::unique_ptr<ChromeMetricsServiceClient> ChromeMetricsServiceClient::Create(
 // static
 void ChromeMetricsServiceClient::RegisterPrefs(PrefRegistrySimple* registry) {
   metrics::MetricsService::RegisterPrefs(registry);
+  ukm::UkmService::RegisterPrefs(registry);
   metrics::StabilityMetricsHelper::RegisterPrefs(registry);
 
   RegisterFileMetricsPreferences(registry);
@@ -337,6 +339,10 @@ metrics::MetricsService* ChromeMetricsServiceClient::GetMetricsService() {
   return metrics_service_.get();
 }
 
+ukm::UkmService* ChromeMetricsServiceClient::GetUkmService() {
+  return ukm_service_.get();
+}
+
 void ChromeMetricsServiceClient::SetMetricsClientId(
     const std::string& client_id) {
   crash_keys::SetMetricsClientIdFromGUID(client_id);
@@ -560,6 +566,9 @@ void ChromeMetricsServiceClient::Initialize() {
   metrics_service_.reset(
       new metrics::MetricsService(metrics_state_manager_, this, local_state));
 
+  if (base::FeatureList::IsEnabled(kUkmFeature))
+    ukm_service_.reset(new ukm::UkmService(local_state, this));
+
   // Gets access to persistent metrics shared by sub-processes.
   metrics_service_->RegisterMetricsProvider(
       std::unique_ptr<metrics::MetricsProvider>(