Convert first contentful paint logging to the new UKM client API

components/ukm/ukm_service.cc

Index: components/ukm/ukm_service.cc
diff --git a/components/ukm/ukm_service.cc b/components/ukm/ukm_service.cc
index 80e1c389706ae65fe3b5b299ed8a76a24ccf1a20..30d7bf6f029a23f02b74c2388aeb744eac15077b 100644
--- a/components/ukm/ukm_service.cc
+++ b/components/ukm/ukm_service.cc
@@ -393,7 +393,7 @@ void UkmService::UpdateSourceURL(int32_t source_id, const GURL& url) {
     if (source_id != source->id())
       continue;
 
-    source->set_committed_url(url);
+    source->set_url(url);
     return;
   }
 
@@ -403,7 +403,7 @@ void UkmService::UpdateSourceURL(int32_t source_id, const GURL& url) {
   }
   std::unique_ptr<UkmSource> source = base::MakeUnique<UkmSource>();
   source->set_id(source_id);
-  source->set_committed_url(url);
+  source->set_url(url);
   sources_.push_back(std::move(source));
 }