Add support for tracking loading behavior of child frames.

chrome/browser/page_load_metrics/page_load_tracker.h

 // Copyright 2016 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.
 
 #ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_TRACKER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_TRACKER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 89 matching lines @@
   // renderer process and the system clock has inter process time tick skew.
   ERR_INTER_PROCESS_TIME_TICK_SKEW,
 
   // At the time a PageLoadTracker was destroyed, we had received neither a
   // commit nor a failed provisional load.
   ERR_NO_COMMIT_OR_FAILED_PROVISIONAL_LOAD,
 
   // No page load end time was recorded for this page load.
   ERR_NO_PAGE_LOAD_END_TIME,
 
+  // Received a timing update from a subframe.
+  ERR_TIMING_IPC_FROM_SUBFRAME,
+
   // Add values before this final count.
   ERR_LAST_ENTRY,
 };
 
 // NOTE: these functions are shared by page_load_tracker.cc and
 // metrics_web_contents_observer.cc. They are declared here to allow both files
 // to access them.
 void RecordInternalError(InternalErrorLoadEvent event);
 PageEndReason EndReasonForPageTransition(ui::PageTransition transition);
 void LogAbortChainSameURLHistogram(int aborted_chain_size_same_url);
@@ skipping 33 matching lines @@
   // killed at any time after this method is invoked without further
   // notification.
   void FlushMetricsOnAppEnterBackground();
 
   void NotifyClientRedirectTo(const PageLoadTracker& destination);
 
   // Returns true if the timing was successfully updated.
   bool UpdateTiming(const PageLoadTiming& timing,
                     const PageLoadMetadata& metadata);
 
+  void UpdateChildMetadata(const PageLoadMetadata& child_metadata);

[Charlie Harrison, 2017/03/09 16:21:29]

I think it deserves a comment for why this is separate from UpdateTiming.

[Bryan McQuade, 2017/03/09 17:36:32]

good idea, done

+
   void OnLoadedResource(const ExtraRequestInfo& extra_request_info);
 
   // Signals that we should stop tracking metrics for the associated page load.
   // We may stop tracking a page load if it doesn't meet the criteria for
   // tracking metrics in DidFinishNavigation.
   void StopTracking();
 
   int aborted_chain_size() const { return aborted_chain_size_; }
   int aborted_chain_size_same_url() const {
     return aborted_chain_size_same_url_;
@@ skipping 114 matching lines @@
   base::TimeTicks page_end_time_;
 
   // We record separate metrics for events that occur after a background,
   // because metrics like layout/paint are delayed artificially
   // when they occur in the background.
   base::TimeTicks background_time_;
   base::TimeTicks foreground_time_;
   bool started_in_foreground_;
 
   PageLoadTiming timing_;
-  PageLoadMetadata metadata_;
+  PageLoadMetadata main_frame_metadata_;
+  PageLoadMetadata child_frame_metadata_;
 
   ui::PageTransition page_transition_;
 
   base::Optional<content::GlobalRequestID> navigation_request_id_;
 
   // Whether this page load was user initiated.
   UserInitiatedInfo user_initiated_info_;
 
   // This is a subtle member. If a provisional load A gets aborted by
   // provisional load B, which gets aborted by C that eventually commits, then
@@ skipping 11 matching lines @@
   PageLoadMetricsEmbedderInterface* const embedder_interface_;
 
   std::vector<std::unique_ptr<PageLoadMetricsObserver>> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PageLoadTracker);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_TRACKER_H_