[PageLoadMetrics] Record bytes usage per page

chrome/browser/page_load_metrics/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 CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_OBSERVER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_OBSERVER_H_
 
 #include "base/macros.h"
 #include "base/optional.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
@@ skipping 100 matching lines @@
       const base::Optional<base::TimeDelta>& first_foreground_time,
       bool started_in_foreground,
       UserInitiatedInfo user_initiated_info,
       const GURL& committed_url,
       const GURL& start_url,
       UserAbortType abort_type,
       UserInitiatedInfo abort_user_initiated_info,
       const base::Optional<base::TimeDelta>& time_to_abort,
       int num_cache_requests,
       int num_network_requests,
+      int64_t cache_bytes,
+      int64_t net_bytes,
       const PageLoadMetadata& metadata);
 
   PageLoadExtraInfo(const PageLoadExtraInfo& other);
 
   ~PageLoadExtraInfo();
 
   // The first time that the page was backgrounded since the navigation started.
   const base::Optional<base::TimeDelta> first_background_time;
 
   // The first time that the page was foregrounded since the navigation started.
@@ skipping 30 matching lines @@
   UserInitiatedInfo abort_user_initiated_info;
 
   const base::Optional<base::TimeDelta> time_to_abort;
 
   // 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;
 
+  // The number of body (not header) prefilter bytes consumed by requests for
+  // the page.
+  int64_t cache_bytes;
+  int64_t network_bytes;
+
   // Extra information supplied to the page load metrics system from the
   // renderer.
   const PageLoadMetadata metadata;
 };
 
 // Interface for PageLoadMetrics observers. All instances of this class are
 // owned by the PageLoadTracker tracking a page load.
 class PageLoadMetricsObserver {
  public:
   // ObservePolicy is used as a return value on some PageLoadMetricsObserver
@@ skipping 110 matching lines @@
   // be invoked for page loads that did not meet the criteria for being tracked
   // at the time the navigation completed. The PageLoadTiming struct contains
   // timing data and the PageLoadExtraInfo struct contains other useful data
   // collected over the course of the page load. Most observers should not need
   // to implement these callbacks, and should implement the On* timing callbacks
   // instead.
 
   // OnComplete is invoked for tracked page loads that committed, immediately
   // before the observer is deleted. Observers that implement OnComplete may
   // also want to implement FlushMetricsOnAppEnterBackground, to avoid loss of
-  // data if the application is killed while in the background.
+  // data if the application is killed while in the background (this happens
+  // frequently on Android).
   virtual void OnComplete(const PageLoadTiming& timing,
                           const PageLoadExtraInfo& extra_info) {}
 
   // OnFailedProvisionalLoad is invoked for tracked page loads that did not
   // commit, immediately before the observer is deleted.
   virtual void OnFailedProvisionalLoad(
       const FailedProvisionalLoadInfo& failed_provisional_load_info,
       const PageLoadExtraInfo& extra_info) {}
 };
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_OBSERVER_H_