PageLoadMetricsObservers observe individual page loads

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 "components/page_load_metrics/browser/page_load_metrics_util.h"
 #include "components/page_load_metrics/common/page_load_timing.h"
 #include "content/public/browser/navigation_handle.h"
 #include "net/base/stale_while_revalidate_experiment_domains.h"
 
 namespace chrome {
 
-StaleWhileRevalidateMetricsObserver::StaleWhileRevalidateMetricsObserver(
-    page_load_metrics::PageLoadMetricsObservable* metrics)
-    : is_interesting_domain_(false), metrics_(metrics) {}
+StaleWhileRevalidateMetricsObserver::StaleWhileRevalidateMetricsObserver()
+    : is_interesting_domain_(false) {}
 
 void StaleWhileRevalidateMetricsObserver::OnCommit(
     content::NavigationHandle* navigation_handle) {
   is_interesting_domain_ = net::IsHostInStaleWhileRevalidateExperimentDomain(
       navigation_handle->GetURL().host());
 }
 
 void StaleWhileRevalidateMetricsObserver::OnComplete(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& extra_info) {
@@ skipping 13 matching lines @@
         timing.first_layout);
   }
   if (!timing.first_text_paint.is_zero()) {
     PAGE_LOAD_HISTOGRAM(
         "PageLoad.Clients.StaleWhileRevalidateExperiment.Timing2."
         "NavigationToFirstTextPaint",
         timing.first_text_paint);
   }
 }
 
-void StaleWhileRevalidateMetricsObserver::OnPageLoadMetricsGoingAway() {
-  metrics_->RemoveObserver(this);
-  delete this;
-}
-
 }  // namespace chrome