[subresource_filter] Use the SubresourceFilterObserver for PageLoadMetrics

chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
index 150b26fae8c4437dd2c618b240936045a9df5e6e..f571301ab26114aa9c4b832eb54899b39c260b89 100644
--- a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
@@ -135,6 +135,10 @@ void LogActivationDecisionMetrics(content::NavigationHandle* navigation_handle,
 
 }  // namespace
 
+SubresourceFilterMetricsObserver::SubresourceFilterMetricsObserver()
+    : scoped_observer_(this) {}
+SubresourceFilterMetricsObserver::~SubresourceFilterMetricsObserver() = default;
+
 page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 SubresourceFilterMetricsObserver::FlushMetricsOnAppEnterBackground(
     const page_load_metrics::mojom::PageLoadTiming& timing,
@@ -147,17 +151,24 @@ SubresourceFilterMetricsObserver::FlushMetricsOnAppEnterBackground(
     OnGoingAway(timing, info, base::TimeTicks::Now());
   return STOP_OBSERVING;
 }
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+SubresourceFilterMetricsObserver::OnStart(
+    content::NavigationHandle* navigation_handle,
+    const GURL& currently_committed_url,
+    bool started_in_foreground) {
+  auto* observer_manager =
+      subresource_filter::SubresourceFilterObserverManager::FromWebContents(
+          navigation_handle->GetWebContents());
+  if (observer_manager)

[Bryan McQuade, 2017/05/23 19:31:57]

what are the cases where observer manager won't exist? will it not exist if
filtering is disabled for instance?

[Charlie Harrison, 2017/05/23 19:58:50]

Only tests :/ I can add a comment.

+    scoped_observer_.Add(observer_manager);
+  return CONTINUE_OBSERVING;
+}
 
 page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 SubresourceFilterMetricsObserver::OnCommit(

[Bryan McQuade, 2017/05/23 19:31:57]

i think we discussed this, but the activation decision will have always been
reported before commit, is that right?

is there any way we can audit this? perhaps if we're registered as a listener,
we can dcheck that activation_decision_.has_value()?

[Charlie Harrison, 2017/05/23 19:58:50]

Done.

     content::NavigationHandle* navigation_handle) {
-  const auto* subres_filter =
-      ContentSubresourceFilterDriverFactory::FromWebContents(
-          navigation_handle->GetWebContents());
-  if (subres_filter)
-    LogActivationDecisionMetrics(
-        navigation_handle,
-        subres_filter->GetActivationDecisionForLastCommittedPageLoad());
+  if (activation_decision_)
+    LogActivationDecisionMetrics(navigation_handle, *activation_decision_);
   return CONTINUE_OBSERVING;
 }
 
@@ -297,6 +308,13 @@ void SubresourceFilterMetricsObserver::MediaStartedPlaying(
   played_media_ = true;
 }
 
+void SubresourceFilterMetricsObserver::OnPageActivationComputed(
+    content::NavigationHandle* navigation_handle,
+    subresource_filter::ActivationDecision activation_decision,
+    const subresource_filter::ActivationState& activation_state) {
+  activation_decision_ = activation_decision;
+}
+
 void SubresourceFilterMetricsObserver::OnGoingAway(
     const page_load_metrics::mojom::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info,