Log First User Interaction in Page Load Metrics

components/page_load_metrics/browser/page_load_metrics_observer.h

 // Copyright 2015 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 COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_OBSERVER_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_OBSERVER_H_
 
 #include "base/macros.h"
 #include "components/page_load_metrics/common/page_load_timing.h"
 #include "content/public/browser/navigation_handle.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "url/gurl.h"
 
 namespace page_load_metrics {
 
 // This enum represents how a page load ends. If the action occurs before the
 // page load finishes (or reaches some point like first paint), then we consider
 // the load to be aborted.
 enum UserAbortType {
   // Represents no abort.
   ABORT_NONE,
@@ skipping 23 matching lines @@
   // navigation it was.
   ABORT_UNKNOWN_NAVIGATION,
 
   // Add values before this final count.
   ABORT_LAST_ENTRY
 };
 
 struct PageLoadExtraInfo {
   PageLoadExtraInfo(base::TimeDelta first_background_time,
                     base::TimeDelta first_foreground_time,
+                    base::TimeDelta first_user_interaction_time,
                     bool started_in_foreground,
                     const GURL& committed_url,
                     base::TimeDelta time_to_commit,
                     UserAbortType abort_type,
                     base::TimeDelta time_to_abort,
                     const PageLoadMetadata& metadata);
   PageLoadExtraInfo(const PageLoadExtraInfo& other);
 
   // The first time that the page was backgrounded since the navigation started.
   // If the page has not been backgrounded this will be base::TimeDelta().
   const base::TimeDelta first_background_time;
 
   // The first time that the page was foregrounded since the navigation started.
   // If the page has not been foregrounded this will be base::TimeDelta().
   const base::TimeDelta first_foreground_time;
 
+  // The first time that the page was given a user input since the navigation
+  // started.
+  const base::TimeDelta first_user_interaction_time;

[Bryan McQuade, 2016/05/25 20:59:23]

just copying an earlier comment i made forward since i didn't see it addressed
(sorry if i missed any comments on it):

i'm actually not sure if this is a generally useful bit of information we want
to be providing in this struct. in particular, if the first interaction happened
before anything was painted (while the screen is blank), is that likely to be
useful to most consumers?

perhaps all consumers should instead implement the OnUserInput callback to store
just the times they are interested in, and we get rid of this TimeDelta in this
struct? If we find that multiple observers are recording the same timestamp
(e.g. first interaction after contentful paint) we can then consider adding it
to this struct and refactoring at that time.

+
   // True if the page load started in the foreground.
   const bool started_in_foreground;
 
   // Committed URL. If the page load did not commit, |committed_url| will be
   // empty.
   const GURL committed_url;
 
   // Time from navigation start until commit. If the page load did not commit,
   // |time_to_commit| will be zero.
   const base::TimeDelta time_to_commit;
@@ skipping 77 matching lines @@
   virtual void OnFirstTextPaint(const PageLoadTiming& timing,
                                 const PageLoadExtraInfo& extra_info) {}
   virtual void OnFirstImagePaint(const PageLoadTiming& timing,
                                  const PageLoadExtraInfo& extra_info) {}
   virtual void OnFirstContentfulPaint(const PageLoadTiming& timing,
                                       const PageLoadExtraInfo& extra_info) {}
   virtual void OnParseStart(const PageLoadTiming& timing,
                             const PageLoadExtraInfo& extra_info) {}
   virtual void OnParseStop(const PageLoadTiming& timing,
                            const PageLoadExtraInfo& extra_info) {}
+
+  // OnUserInput is triggered when a new user input is passed in to
+  // web_contents

[tdresser, 2016/05/24 14:28:38]

Missing .

+  virtual void OnUserInput(const blink::WebInputEvent& event) {}
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_OBSERVER_H_