Improve tracking of user initiated page loads.

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 229 matching lines @@
 
   // The start URL for this page load (before redirects).
   GURL start_url_;
 
   std::unique_ptr<FailedProvisionalLoadInfo> failed_provisional_load_info_;
 
   // Will be ABORT_NONE if we have not aborted this load yet. Otherwise will
   // be the first abort action the user performed.
   UserAbortType abort_type_;
 
-  // This boolean is only an approximation. As the aborts pipeline is updated,

[Bryan McQuade, 2016/11/10 15:51:22]

I changed this comment as I feel this kind of comment is really more about the
limitations of user initiated navigation tracking in general than it is specific
to user-initiated abort tracking.

The 'this is only set for navigations aborting navigations' also isn't totally
accurate anymore now that a page backgrounding can cause an abort with an abort
type of 'background' so I removed it.

[Charlie Harrison, 2016/11/10 20:33:04]

I'd like the comment to remain general, as it is important that we eventually
distinguish e.g. non-navigational aborts as user initiated or not (i.e. tab
close vs process OOM).

[Bryan McQuade, 2016/11/10 20:58:18]

Makes sense. I updated the comment to be a little more specific, and to reflect
the change that we now track some non-nav-related user initiated aborts.

-  // more abort types will have this set to true. Currently, this is only set
-  // for navigations aborting navigations.
+  // Whether the page load that aborted this page load was user initiated. Only
+  // set if this page load's abort type is set to a value other than ABORT_NONE.
   bool abort_user_initiated_;
 
   base::TimeTicks abort_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_;
 
   ui::PageTransition page_transition_;
 
   // Note: these are only approximations, based on WebContents attribution from
   // ResourceRequestInfo objects while this is the currently committed load in
   // the WebContents.
   int num_cache_requests_;
   int num_network_requests_;
 
   // This is derived from the user gesture bit in the renderer. For browser
   // initiated navigations this will always be true.
-  bool user_gesture_;
+  bool user_initiated_;
 
   // 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
   // there exists an abort chain of length 2, starting at A's navigation_start.
   // This is useful because it allows histograming abort chain lengths based on
   // what the last load's transition type is. i.e. holding down F-5 to spam
   // reload will produce a long chain with the RELOAD transition.
   const int aborted_chain_size_;
 
   // This member counts consecutive provisional aborts that share a url. It will
   // always be less than or equal to |aborted_chain_size_|.
   const int aborted_chain_size_same_url_;
 
   // Interface to chrome features. Must outlive the class.
   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_