1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
6#define CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
7
8#include <string>
9
10#include "base/time/time.h"
11#include "chrome/browser/prerender/prerender_contents.h"
12#include "chrome/browser/prerender/prerender_final_status.h"
13#include "chrome/browser/prerender/prerender_local_predictor.h"
14#include "chrome/browser/prerender/prerender_origin.h"
15#include "url/gurl.h"
16
17namespace prerender {
18
19// PrerenderHistograms is responsible for recording all prerender specific
20// histograms for PrerenderManager.  It keeps track of the type of prerender
21// currently underway (based on the PrerenderOrigin of the most recent
22// prerenders, and any experiments detected).
23// PrerenderHistograms does not necessarily record all histograms related to
24// prerendering, only the ones in the context of PrerenderManager.
25class PrerenderHistograms {
26 public:
27  // Owned by a PrerenderManager object for the lifetime of the
28  // PrerenderManager.
29  PrerenderHistograms();
30
31  // Records the perceived page load time for a page - effectively the time from
32  // when the user navigates to a page to when it finishes loading.  The actual
33  // load may have started prior to navigation due to prerender hints.
34  void RecordPerceivedPageLoadTime(Origin origin,
35                                   base::TimeDelta perceived_page_load_time,
36                                   bool was_prerender,
37                                   bool was_complete_prerender,
38                                   const GURL& url);
39
40  // Records, in a histogram, the percentage of the page load time that had
41  // elapsed by the time it is swapped in.  Values outside of [0, 1.0] are
42  // invalid and ignored.
43  void RecordPercentLoadDoneAtSwapin(Origin origin, double fraction) const;
44
45  // Records the actual pageload time of a prerender that has not been swapped
46  // in yet, but finished loading.
47  void RecordPageLoadTimeNotSwappedIn(Origin origin,
48                                      base::TimeDelta page_load_time,
49                                      const GURL& url) const;
50
51  // Records the time from when a page starts prerendering to when the user
52  // navigates to it. This must be called on the UI thread.
53  void RecordTimeUntilUsed(Origin origin,
54                           base::TimeDelta time_until_used) const;
55
56  // Record a PerSessionCount data point.
57  void RecordPerSessionCount(Origin origin, int count) const;
58
59  // Record time between two prerender requests.
60  void RecordTimeBetweenPrerenderRequests(Origin origin,
61                                          base::TimeDelta time) const;
62
63  // Record a final status of a prerendered page in a histogram.
64  void RecordFinalStatus(Origin origin,
65                         uint8 experiment_id,
66                         PrerenderContents::MatchCompleteStatus mc_status,
67                         FinalStatus final_status) const;
68
69  // To be called when a new prerender is added.
70  void RecordPrerender(Origin origin, const GURL& url);
71
72  // To be called when a new prerender is started.
73  void RecordPrerenderStarted(Origin origin) const;
74
75  // To be called when we know how many prerenders are running after starting
76  // a prerender.
77  void RecordConcurrency(size_t prerender_count) const;
78
79  // Called when we swap in a prerender.
80  void RecordUsedPrerender(Origin origin) const;
81
82  // Record the time since a page was recently visited.
83  void RecordTimeSinceLastRecentVisit(Origin origin,
84                                      base::TimeDelta time) const;
85
86  // Record a percentage of pixels of the final page already in place at
87  // swap-in.
88  void RecordFractionPixelsFinalAtSwapin(Origin origin, double fraction) const;
89
90 private:
91  base::TimeTicks GetCurrentTimeTicks() const;
92
93  // Returns the time elapsed since the last prerender happened.
94  base::TimeDelta GetTimeSinceLastPrerender() const;
95
96  // Returns whether the PrerenderManager is currently within the prerender
97  // window - effectively, up to 30 seconds after a prerender tag has been
98  // observed.
99  bool WithinWindow() const;
100
101  // Returns the current experiment.
102  uint8 GetCurrentExperimentId() const;
103
104  // Returns whether or not there is currently an origin/experiment wash.
105  bool IsOriginExperimentWash() const;
106
107  // An integer indicating a Prerendering Experiment being currently conducted.
108  // (The last experiment ID seen).
109  uint8 last_experiment_id_;
110
111  // Origin of the last prerender seen.
112  Origin last_origin_;
113
114  // A boolean indicating that we have recently encountered a combination of
115  // different experiments and origins, making an attribution of PPLT's to
116  // experiments / origins impossible.
117  bool origin_experiment_wash_;
118
119  // The time when we last saw a prerender request coming from a renderer.
120  // This is used to record perceived PLT's for a certain amount of time
121  // from the point that we last saw a <link rel=prerender> tag.
122  base::TimeTicks last_prerender_seen_time_;
123
124  // Indicates whether we have recorded page load events after the most
125  // recent prerender.  These must be initialized to true, so that we don't
126  // start recording events before the first prerender occurs.
127  bool seen_any_pageload_;
128  bool seen_pageload_started_after_prerender_;
129
130  DISALLOW_COPY_AND_ASSIGN(PrerenderHistograms);
131};
132
133}  // namespace prerender
134
135#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
136