Histogram the amount of time spent on HTTP(S) page loads

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"
@@ skipping 87 matching lines @@
 
   // The page load started, with the given navigation handle. Note that OnStart
   // is called for same-page navigations. Implementers of OnStart that only want
   // to process non-same-page navigations should also check to see that the page
   // load committed via OnCommit or committed_url in
   // PageLoadExtraInfo. currently_committed_url contains the URL of the
   // committed page load at the time the navigation for navigation_handle was
   // initiated, or the empty URL if there was no committed page load at the time
   // the navigation was initiated.
   virtual void OnStart(content::NavigationHandle* navigation_handle,
-                       const GURL& currently_committed_url) {}
+                       const GURL& currently_committed_url,
+                       bool started_in_foreground) {}
 
   // OnRedirect is triggered when a page load redirects to another URL.
   // The navigation handle holds relevant data for the navigation, but will
   // be destroyed soon after this call. Don't hold a reference to it. This can
   // be called multiple times.
   virtual void OnRedirect(content::NavigationHandle* navigation_handle) {}
 
   // OnCommit is triggered when a page load commits, i.e. when we receive the
   // first data for the request. The navigation handle holds relevant data for
   // the navigation, but will be destroyed soon after this call. Don't hold a
   // reference to it.
   // Note that this does not get called for same page navigations.
   virtual void OnCommit(content::NavigationHandle* navigation_handle) {}
 
   // OnFailedProvisionalLoad is triggered when a provisional load failed and did
   // not commit. Note that provisional loads that result in downloads or 204s
   // are aborted by the system, and thus considered failed provisional loads.
   virtual void OnFailedProvisionalLoad(
       content::NavigationHandle* navigation_handle) {}
 
   // OnTimingUpdate is triggered when an updated PageLoadTiming is
   // available. This method may be called multiple times over the course of the
   // page load. Note that this is currently an experimental API which may be
   // removed in the future. Please email loading-dev@chromium.org if you intend
   // to override this method.
   virtual void OnTimingUpdate(const PageLoadTiming& timing,
                               const PageLoadExtraInfo& extra_info) {}
 
+  // OnHidden is triggered when a page leaves the foreground. It does not fire
+  // when a foreground page is permanently closed; for that, listen to
+  // OnComplete instead.
+  virtual void OnHidden() {}
+
+  // OnShown is triggered when a page is brought to the foreground. It does not
+  // fire when the page first loads; for that, listen for OnStart instead.
+  virtual void OnShown() {}
+
   // OnComplete is triggered when we are ready to record metrics for this page
   // load. This will happen some time after commit. The PageLoadTiming struct
   // contains timing data and the PageLoadExtraInfo struct contains other useful
   // data collected over the course of the page load. If the load did not
   // receive any timing information, |timing.IsEmpty()| will be true.
   // After this call, the object will be deleted.
   virtual void OnComplete(const PageLoadTiming& timing,
                           const PageLoadExtraInfo& extra_info) {}
 
   // The following methods are invoked at most once, when the timing for the
@@ skipping 15 matching lines @@
                                       const PageLoadExtraInfo& extra_info) {}
   virtual void OnParseStart(const PageLoadTiming& timing,
                             const PageLoadExtraInfo& extra_info) {}
   virtual void OnParseStop(const PageLoadTiming& timing,
                            const PageLoadExtraInfo& extra_info) {}
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_OBSERVER_H_