1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
// Copyright (c) 2012 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.
#include "chrome/browser/prerender/prerender_field_trial.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram.h"
#include "chrome/browser/metrics/metrics_service.h"
#include "chrome/browser/predictors/autocomplete_action_predictor.h"
#include "chrome/browser/prefs/pref_service.h"
#include "chrome/browser/prerender/prerender_manager.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/chrome_version_info.h"
namespace prerender {
namespace {
const char kOmniboxTrialName[] = "PrerenderFromOmnibox";
int g_omnibox_trial_default_group_number = -1;
void SetupPrefetchFieldTrial() {
chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
channel == chrome::VersionInfo::CHANNEL_BETA) {
return;
}
const base::FieldTrial::Probability divisor = 1000;
const base::FieldTrial::Probability prefetch_probability = 500;
scoped_refptr<base::FieldTrial> trial(
base::FieldTrialList::FactoryGetFieldTrial(
"Prefetch", divisor, "ContentPrefetchPrefetchOff",
2013, 6, 30, NULL));
const int kPrefetchOnGroup = trial->AppendGroup("ContentPrefetchPrefetchOn",
prefetch_probability);
PrerenderManager::SetIsPrefetchEnabled(trial->group() == kPrefetchOnGroup);
}
void SetupPrerenderFieldTrial() {
base::FieldTrial::Probability divisor = 1000;
base::FieldTrial::Probability exp1_probability = 166;
base::FieldTrial::Probability exp1_5min_ttl_probability = 83;
base::FieldTrial::Probability control1_probability = 166;
base::FieldTrial::Probability no_use1_probability = 83;
base::FieldTrial::Probability exp2_probability = 167;
base::FieldTrial::Probability exp2_5min_ttl_probability = 84;
base::FieldTrial::Probability control2_probability = 167;
base::FieldTrial::Probability no_use2_probability = 84;
chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
channel == chrome::VersionInfo::CHANNEL_BETA) {
exp1_probability = 490;
exp1_5min_ttl_probability = 5;
control1_probability = 5;
no_use1_probability = 0;
exp2_probability = 490;
exp2_5min_ttl_probability = 5;
control2_probability = 5;
no_use2_probability = 0;
}
CHECK_EQ(divisor, exp1_probability + exp1_5min_ttl_probability +
control1_probability + no_use1_probability + exp2_probability +
exp2_5min_ttl_probability + control2_probability +
no_use2_probability);
int experiment_1_group = -1;
scoped_refptr<base::FieldTrial> trial(
base::FieldTrialList::FactoryGetFieldTrial(
"Prerender", divisor, "ContentPrefetchPrerender1",
2013, 6, 30, &experiment_1_group));
const int experiment_15_min_TTL_group =
trial->AppendGroup("ContentPrefetchPrerenderExp5minTTL1",
exp1_5min_ttl_probability);
const int control_1_group =
trial->AppendGroup("ContentPrefetchPrerenderControl1",
control1_probability);
const int no_use_1_group =
trial->AppendGroup("ContentPrefetchPrerenderNoUse1",
no_use1_probability);
const int experiment_2_group =
trial->AppendGroup("ContentPrefetchPrerender2",
exp2_probability);
const int experiment_25_min_TTL_group =
trial->AppendGroup("ContentPrefetchPrerenderExp5minTTL2",
exp2_5min_ttl_probability);
const int control_2_group =
trial->AppendGroup("ContentPrefetchPrerenderControl2",
control2_probability);
const int no_use_2_group =
trial->AppendGroup("ContentPrefetchPrerenderNoUse2",
no_use2_probability);
const int trial_group = trial->group();
if (trial_group == experiment_1_group ||
trial_group == experiment_2_group) {
PrerenderManager::SetMode(
PrerenderManager::PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP);
} else if (trial_group == experiment_15_min_TTL_group ||
trial_group == experiment_25_min_TTL_group) {
PrerenderManager::SetMode(
PrerenderManager::PRERENDER_MODE_EXPERIMENT_5MIN_TTL_GROUP);
} else if (trial_group == control_1_group ||
trial_group == control_2_group) {
PrerenderManager::SetMode(
PrerenderManager::PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP);
} else if (trial_group == no_use_1_group ||
trial_group == no_use_2_group) {
PrerenderManager::SetMode(
PrerenderManager::PRERENDER_MODE_EXPERIMENT_NO_USE_GROUP);
} else {
NOTREACHED();
}
}
} // end namespace
void ConfigureOmniboxPrerender();
void ConfigurePrefetchAndPrerender(const CommandLine& command_line) {
enum PrerenderOption {
PRERENDER_OPTION_AUTO,
PRERENDER_OPTION_DISABLED,
PRERENDER_OPTION_ENABLED,
PRERENDER_OPTION_PREFETCH_ONLY,
};
PrerenderOption prerender_option = PRERENDER_OPTION_AUTO;
if (command_line.HasSwitch(switches::kPrerenderMode)) {
const std::string switch_value =
command_line.GetSwitchValueASCII(switches::kPrerenderMode);
if (switch_value == switches::kPrerenderModeSwitchValueAuto) {
prerender_option = PRERENDER_OPTION_AUTO;
} else if (switch_value == switches::kPrerenderModeSwitchValueDisabled) {
prerender_option = PRERENDER_OPTION_DISABLED;
} else if (switch_value.empty() ||
switch_value == switches::kPrerenderModeSwitchValueEnabled) {
// The empty string means the option was provided with no value, and that
// means enable.
prerender_option = PRERENDER_OPTION_ENABLED;
} else if (switch_value ==
switches::kPrerenderModeSwitchValuePrefetchOnly) {
prerender_option = PRERENDER_OPTION_PREFETCH_ONLY;
} else {
prerender_option = PRERENDER_OPTION_DISABLED;
LOG(ERROR) << "Invalid --prerender option received on command line: "
<< switch_value;
LOG(ERROR) << "Disabling prerendering!";
}
}
switch (prerender_option) {
case PRERENDER_OPTION_AUTO:
SetupPrefetchFieldTrial();
SetupPrerenderFieldTrial();
break;
case PRERENDER_OPTION_DISABLED:
PrerenderManager::SetIsPrefetchEnabled(false);
PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_DISABLED);
break;
case PRERENDER_OPTION_ENABLED:
PrerenderManager::SetIsPrefetchEnabled(true);
PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
break;
case PRERENDER_OPTION_PREFETCH_ONLY:
PrerenderManager::SetIsPrefetchEnabled(true);
PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_DISABLED);
break;
default:
NOTREACHED();
}
UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
PrerenderManager::GetMode(),
PrerenderManager::PRERENDER_MODE_MAX);
ConfigureOmniboxPrerender();
}
void ConfigureOmniboxPrerender() {
// Field trial to see if we're enabled.
const base::FieldTrial::Probability kDivisor = 100;
base::FieldTrial::Probability kDisabledProbability = 10;
chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
channel == chrome::VersionInfo::CHANNEL_BETA) {
kDisabledProbability = 1;
}
scoped_refptr<base::FieldTrial> omnibox_prerender_trial(
base::FieldTrialList::FactoryGetFieldTrial(
kOmniboxTrialName, kDivisor, "OmniboxPrerenderEnabled",
2012, 12, 30, &g_omnibox_trial_default_group_number));
omnibox_prerender_trial->AppendGroup("OmniboxPrerenderDisabled",
kDisabledProbability);
}
bool IsOmniboxEnabled(Profile* profile) {
if (!profile)
return false;
if (!PrerenderManager::IsPrerenderingPossible())
return false;
// Override any field trial groups if the user has set a command line flag.
if (CommandLine::ForCurrentProcess()->HasSwitch(
switches::kPrerenderFromOmnibox)) {
const std::string switch_value =
CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
switches::kPrerenderFromOmnibox);
if (switch_value == switches::kPrerenderFromOmniboxSwitchValueEnabled)
return true;
if (switch_value == switches::kPrerenderFromOmniboxSwitchValueDisabled)
return false;
DCHECK(switch_value == switches::kPrerenderFromOmniboxSwitchValueAuto);
}
const int group = base::FieldTrialList::FindValue(kOmniboxTrialName);
return group == base::FieldTrial::kNotFinalized ||
group == g_omnibox_trial_default_group_number;
}
} // namespace prerender
|
