Add support for tracking loading behavior of child frames.

chrome/browser/page_load_metrics/page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_observer.h b/chrome/browser/page_load_metrics/page_load_metrics_observer.h
index 370d95c2dff214c69c641a9dc73ab3eb713ca155..2761722d532f5ef7fa032c391574a386fe05e582 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/page_load_metrics_observer.h
@@ -118,7 +118,8 @@ struct PageLoadExtraInfo {
       PageEndReason page_end_reason,
       UserInitiatedInfo page_end_user_initiated_info,
       const base::Optional<base::TimeDelta>& page_end_time,
-      const PageLoadMetadata& metadata);
+      const PageLoadMetadata& metadata,
+      int child_loading_behavior_flags);
 
   // Simplified version of the constructor, intended for use in tests.
   static PageLoadExtraInfo CreateForTesting(const GURL& url,
@@ -188,6 +189,9 @@ struct PageLoadExtraInfo {
   // Extra information supplied to the page load metrics system from the
   // renderer.
   const PageLoadMetadata metadata;
+
+  // WebLoadingBehaviorFlags for child frames of the current page.
+  const int child_loading_behavior_flags;

[Charlie Harrison, 2017/03/08 21:47:17]

I would prefer either
1. Make this a full blown PageLoadMetadata
2. Put this int in the existing metadata.

[Bryan McQuade, 2017/03/09 03:06:11]

sure, switched to a separate PageLoadMetadata

 };
 
 // Container for various information about a request within a page load.
@@ -314,7 +318,8 @@ class PageLoadMetricsObserver {
   virtual void OnParseStop(const PageLoadTiming& timing,
                            const PageLoadExtraInfo& extra_info) {}
 
-  // Invoked when there is a change in PageLoadMetadata's behavior_flags.
+  // Invoked when there is a change in either PageLoadMetadata's behavior_flags,
+  // or the child_loading_behavior_flags.
   virtual void OnLoadingBehaviorObserved(
       const page_load_metrics::PageLoadExtraInfo& extra_info) {}