Update OnCommit to return ObservePolicy.

chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/page_load_metrics/observers/stale_while_revalidate_metrics_observer.h"
 
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
 #include "content/public/browser/navigation_handle.h"
 #include "net/base/stale_while_revalidate_experiment_domains.h"
 
 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(
     const page_load_metrics::PageLoadTiming& timing,
     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(
         "PageLoad.Clients.StaleWhileRevalidateExperiment.Timing2."
         "NavigationToLoadEventFired",
         timing.load_event_start.value());
   }
   if (WasStartedInForegroundOptionalEventInForeground(timing.first_layout,
                                                       extra_info)) {
     PAGE_LOAD_HISTOGRAM(
         "PageLoad.Clients.StaleWhileRevalidateExperiment.Timing2."
         "NavigationToFirstLayout",
         timing.first_layout.value());
   }
   if (WasStartedInForegroundOptionalEventInForeground(timing.first_text_paint,
                                                       extra_info)) {
     PAGE_LOAD_HISTOGRAM(
         "PageLoad.Clients.StaleWhileRevalidateExperiment.Timing2."
         "NavigationToFirstTextPaint",
         timing.first_text_paint.value());
   }
 }
 
 }  // namespace chrome