Add metric with time between background tab being foregrounded and the first paint

components/page_load_metrics/browser/page_load_metrics_util.cc

Index: components/page_load_metrics/browser/page_load_metrics_util.cc
diff --git a/components/page_load_metrics/browser/page_load_metrics_util.cc b/components/page_load_metrics/browser/page_load_metrics_util.cc
index 913b141f2d3815776fa74efc4c691f5db056dcaf..dbfa35ebad04390d702be6642f8a546ce3715e76 100644
--- a/components/page_load_metrics/browser/page_load_metrics_util.cc
+++ b/components/page_load_metrics/browser/page_load_metrics_util.cc
@@ -11,8 +11,8 @@
 
 namespace page_load_metrics {
 
-bool EventOccurredInForeground(base::TimeDelta event,
-                               const PageLoadExtraInfo& info) {
+bool WasStartedInForegroundEventInForeground(base::TimeDelta event,
+                                             const PageLoadExtraInfo& info) {
   return info.started_in_foreground && !event.is_zero() &&
          (info.first_background_time.is_zero() ||
           event < info.first_background_time);