Revert 146170 - Adding a field trial to enable speculative resource prefetching learning.

chrome/browser/prerender/prerender_field_trial.cc

 // 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;
 
-const char kSpeculativePrefetchingLearningTrialName[] =
-    "SpeculativePrefetchingLearning";
-int g_speculative_prefetching_learning_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(
@@ skipping 79 matching lines @@
     PrerenderManager::SetMode(
         PrerenderManager::PRERENDER_MODE_EXPERIMENT_NO_USE_GROUP);
   } else {
     NOTREACHED();
   }
 }
 
 }  // end namespace
 
 void ConfigureOmniboxPrerender();
-void ConfigureSpeculativePrefetching();
 
 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;
@@ skipping 40 matching lines @@
       break;
     default:
       NOTREACHED();
   }
 
   UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
                             PrerenderManager::GetMode(),
                             PrerenderManager::PRERENDER_MODE_MAX);
 
   ConfigureOmniboxPrerender();
-  ConfigureSpeculativePrefetching();
 }
 
 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) {
@@ skipping 28 matching lines @@
       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;
 }
 
-void ConfigureSpeculativePrefetching() {
-  // Field trial to see if we're enabled.
-  const base::FieldTrial::Probability kDivisor = 100;
-
-  base::FieldTrial::Probability kDisabledProbability = 99;
-  chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
-  if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
-      channel == chrome::VersionInfo::CHANNEL_BETA) {
-    kDisabledProbability = 100;
-  }
-  scoped_refptr<base::FieldTrial> speculative_prefetching_learning_trial(
-      base::FieldTrialList::FactoryGetFieldTrial(
-          kSpeculativePrefetchingLearningTrialName,
-          kDivisor,
-          "SpeculativePrefetchingLearningEnabled",
-          2012, 12, 30,
-          &g_speculative_prefetching_learning_default_group_number));
-  speculative_prefetching_learning_trial->AppendGroup(
-      "SpeculativePrefetchingDisabled",
-      kDisabledProbability);
-}
-
-bool IsSpeculativeResourcePrefetchingLearningEnabled(Profile* profile) {
-  if (!profile)
-    return false;
-
-  // Override any field trial groups if the user has set a command line flag.
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSpeculativeResourcePrefetching)) {
-    const std::string switch_value =
-        CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-            switches::kSpeculativeResourcePrefetching);
-
-    if (switch_value == switches::kSpeculativeResourcePrefetchingLearning)
-      return true;
-  }
-
-  const int group = base::FieldTrialList::FindValue(
-      kSpeculativePrefetchingLearningTrialName);
-  return group == g_speculative_prefetching_learning_default_group_number;
-}
-
 }  // namespace prerender