1 // Copyright (c) 2011 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 #include "chrome/browser/prerender/prerender_field_trial.h"
6
7 #include "base/command_line.h"
8 #include "base/logging.h"
9 #include "base/metrics/field_trial.h"
10 #include "base/metrics/histogram.h"
11 #include "content/browser/renderer_host/resource_dispatcher_host.h"
12 #include "chrome/browser/prerender/prerender_manager.h"
13 #include "chrome/common/chrome_switches.h"
14
15
16 namespace prerender {
17
ConfigurePrefetchAndPrerender(const CommandLine & command_line)18 void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
19 enum PrerenderOption {
20 PRERENDER_OPTION_AUTO,
21 PRERENDER_OPTION_DISABLED,
22 PRERENDER_OPTION_ENABLED,
23 PRERENDER_OPTION_PREFETCH_ONLY,
24 };
25
26 PrerenderOption prerender_option = PRERENDER_OPTION_AUTO;
27 if (command_line.HasSwitch(switches::kPrerender)) {
28 const std::string switch_value =
29 command_line.GetSwitchValueASCII(switches::kPrerender);
30
31 if (switch_value == switches::kPrerenderSwitchValueAuto) {
32 #if defined(OS_CHROMEOS)
33 // Prerender is temporarily disabled on CrOS.
34 // http://crosbug.com/12483
35 prerender_option = PRERENDER_OPTION_DISABLED;
36 #else
37 prerender_option = PRERENDER_OPTION_AUTO;
38 #endif
39 } else if (switch_value == switches::kPrerenderSwitchValueDisabled) {
40 prerender_option = PRERENDER_OPTION_DISABLED;
41 } else if (switch_value.empty() ||
42 switch_value == switches::kPrerenderSwitchValueEnabled) {
43 // The empty string means the option was provided with no value, and that
44 // means enable.
45 prerender_option = PRERENDER_OPTION_ENABLED;
46 } else if (switch_value == switches::kPrerenderSwitchValuePrefetchOnly) {
47 prerender_option = PRERENDER_OPTION_PREFETCH_ONLY;
48 } else {
49 prerender_option = PRERENDER_OPTION_DISABLED;
50 LOG(ERROR) << "Invalid --prerender option received on command line: "
51 << switch_value;
52 LOG(ERROR) << "Disabling prerendering!";
53 }
54 }
55
56 switch (prerender_option) {
57 case PRERENDER_OPTION_AUTO: {
58 const base::FieldTrial::Probability kPrefetchDivisor = 1000;
59 const base::FieldTrial::Probability kYesPrefetchProbability = 0;
60 const base::FieldTrial::Probability kPrerenderExp1Probability = 0;
61 const base::FieldTrial::Probability kPrerenderControl1Probability = 0;
62 const base::FieldTrial::Probability kPrerenderExp2Probability = 0;
63 const base::FieldTrial::Probability kPrerenderControl2Probability = 0;
64
65 scoped_refptr<base::FieldTrial> trial(
66 new base::FieldTrial("Prefetch", kPrefetchDivisor,
67 "ContentPrefetchDisabled", 2011, 6, 30));
68
69 const int kNoPrefetchGroup = trial->kDefaultGroupNumber;
70 const int kYesPrefetchGroup =
71 trial->AppendGroup("ContentPrefetchEnabled", kYesPrefetchProbability);
72 const int kPrerenderExperiment1Group =
73 trial->AppendGroup("ContentPrefetchPrerender1",
74 kPrerenderExp1Probability);
75 const int kPrerenderControl1Group =
76 trial->AppendGroup("ContentPrefetchPrerenderControl1",
77 kPrerenderControl1Probability);
78 const int kPrerenderExperiment2Group =
79 trial->AppendGroup("ContentPrefetchPrerender2",
80 kPrerenderExp2Probability);
81 const int kPrerenderControl2Group =
82 trial->AppendGroup("ContentPrefetchPrerenderControl2",
83 kPrerenderControl2Probability);
84 const int trial_group = trial->group();
85 if (trial_group == kYesPrefetchGroup) {
86 ResourceDispatcherHost::set_is_prefetch_enabled(true);
87 PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_DISABLED);
88 } else if (trial_group == kNoPrefetchGroup) {
89 ResourceDispatcherHost::set_is_prefetch_enabled(false);
90 PrerenderManager::SetMode(
91 PrerenderManager::PRERENDER_MODE_DISABLED);
92 } else if (trial_group == kPrerenderExperiment1Group ||
93 trial_group == kPrerenderExperiment2Group) {
94 ResourceDispatcherHost::set_is_prefetch_enabled(true);
95 PrerenderManager::SetMode(
96 PrerenderManager::PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP);
97 } else if (trial_group == kPrerenderControl1Group ||
98 trial_group == kPrerenderControl2Group) {
99 ResourceDispatcherHost::set_is_prefetch_enabled(true);
100 PrerenderManager::SetMode(
101 PrerenderManager::PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP);
102 } else {
103 NOTREACHED();
104 }
105 break;
106 }
107 case PRERENDER_OPTION_DISABLED:
108 ResourceDispatcherHost::set_is_prefetch_enabled(false);
109 PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_DISABLED);
110 break;
111 case PRERENDER_OPTION_ENABLED:
112 ResourceDispatcherHost::set_is_prefetch_enabled(true);
113 PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
114 break;
115 case PRERENDER_OPTION_PREFETCH_ONLY:
116 ResourceDispatcherHost::set_is_prefetch_enabled(true);
117 PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_DISABLED);
118 break;
119 default:
120 NOTREACHED();
121 }
122
123 UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
124 PrerenderManager::GetMode(),
125 PrerenderManager::PRERENDER_MODE_MAX);
126 }
127
128 } // namespace prerender
129