Update OnCommit to return ObservePolicy.

chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc
index 774eb5b66cd8ec8a1bf6113f4e5157f3a6e47142..56981a3f71bc362fdae31de14f501d6887620499 100644
--- a/chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.cc
@@ -39,21 +39,22 @@ const char kHistogramOfflinePreviewsParseStart[] =
 
 }  // namespace internal
 
-PreviewsPageLoadMetricsObserver::PreviewsPageLoadMetricsObserver()
-    : is_offline_preview_(false) {}
+PreviewsPageLoadMetricsObserver::PreviewsPageLoadMetricsObserver() {}
 
 PreviewsPageLoadMetricsObserver::~PreviewsPageLoadMetricsObserver() {}
 
-void PreviewsPageLoadMetricsObserver::OnCommit(
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+PreviewsPageLoadMetricsObserver::OnCommit(
     content::NavigationHandle* navigation_handle) {
-  is_offline_preview_ = IsOfflinePreview(navigation_handle->GetWebContents());
+  return IsOfflinePreview(navigation_handle->GetWebContents())
+             ? CONTINUE_OBSERVING
+             : STOP_OBSERVING;
 }
 
 void PreviewsPageLoadMetricsObserver::OnDomContentLoadedEventStart(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
-  if (!is_offline_preview_ ||
-      !WasStartedInForegroundOptionalEventInForeground(
+  if (!WasStartedInForegroundOptionalEventInForeground(
           timing.dom_content_loaded_event_start, info)) {
     return;
   }
@@ -65,8 +66,7 @@ void PreviewsPageLoadMetricsObserver::OnDomContentLoadedEventStart(
 void PreviewsPageLoadMetricsObserver::OnLoadEventStart(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
-  if (!is_offline_preview_ ||
-      !WasStartedInForegroundOptionalEventInForeground(
+  if (!WasStartedInForegroundOptionalEventInForeground(
           timing.dom_content_loaded_event_start, info)) {
     return;
   }
@@ -77,8 +77,7 @@ void PreviewsPageLoadMetricsObserver::OnLoadEventStart(
 void PreviewsPageLoadMetricsObserver::OnFirstLayout(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
-  if (!is_offline_preview_ ||
-      !WasStartedInForegroundOptionalEventInForeground(
+  if (!WasStartedInForegroundOptionalEventInForeground(
           timing.dom_content_loaded_event_start, info)) {
     return;
   }
@@ -89,8 +88,7 @@ void PreviewsPageLoadMetricsObserver::OnFirstLayout(
 void PreviewsPageLoadMetricsObserver::OnFirstContentfulPaint(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
-  if (!is_offline_preview_ ||
-      !WasStartedInForegroundOptionalEventInForeground(
+  if (!WasStartedInForegroundOptionalEventInForeground(
           timing.dom_content_loaded_event_start, info)) {
     return;
   }
@@ -101,8 +99,7 @@ void PreviewsPageLoadMetricsObserver::OnFirstContentfulPaint(
 void PreviewsPageLoadMetricsObserver::OnParseStart(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
-  if (!is_offline_preview_ ||
-      !WasStartedInForegroundOptionalEventInForeground(
+  if (!WasStartedInForegroundOptionalEventInForeground(
           timing.dom_content_loaded_event_start, info)) {
     return;
   }