Update OnCommit to return ObservePolicy.

chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc
index 3299d3a3f96deb8e2fbb6259ec7c9bbe87b25bda..88012dae64b7b329227e807914cdd2c8314a7c70 100644
--- a/chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc
@@ -11,13 +11,15 @@
 
 namespace chrome {
 
-StaleWhileRevalidateMetricsObserver::StaleWhileRevalidateMetricsObserver()
-    : is_interesting_domain_(false) {}
+StaleWhileRevalidateMetricsObserver::StaleWhileRevalidateMetricsObserver() {}
 
-void StaleWhileRevalidateMetricsObserver::OnCommit(
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+StaleWhileRevalidateMetricsObserver::OnCommit(
     content::NavigationHandle* navigation_handle) {
-  is_interesting_domain_ = net::IsHostInStaleWhileRevalidateExperimentDomain(
-      navigation_handle->GetURL().host());
+  return net::IsHostInStaleWhileRevalidateExperimentDomain(
+             navigation_handle->GetURL().host())
+             ? CONTINUE_OBSERVING
+             : STOP_OBSERVING;
 }
 
 void StaleWhileRevalidateMetricsObserver::OnComplete(
@@ -25,9 +27,6 @@ void StaleWhileRevalidateMetricsObserver::OnComplete(
     const page_load_metrics::PageLoadExtraInfo& extra_info) {
   using page_load_metrics::WasStartedInForegroundOptionalEventInForeground;
 
-  if (!is_interesting_domain_)
-    return;
-
   if (WasStartedInForegroundOptionalEventInForeground(timing.load_event_start,
                                                       extra_info)) {
     PAGE_LOAD_HISTOGRAM(