[Cleanup] Remove some expired omnibox field trials.

components/omnibox/browser/omnibox_field_trial.cc

 // Copyright 2014 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 "components/omnibox/browser/omnibox_field_trial.h"
 
 #include <cmath>
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
-#include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "components/metrics/proto/omnibox_event.pb.h"
 #include "components/omnibox/browser/omnibox_switches.h"
 #include "components/search/search.h"
 #include "components/variations/active_field_trials.h"
 #include "components/variations/metrics_util.h"
 #include "components/variations/variations_associated_data.h"
 
 using metrics::OmniboxEventProto;
 
 namespace {
 
 typedef std::map<std::string, std::string> VariationParams;
 typedef HUPScoringParams::ScoreBuckets ScoreBuckets;
 
 // Field trial names.
 const char kStopTimerFieldTrialName[] = "OmniboxStopTimer";
 
-// The autocomplete dynamic field trial name prefix.  Each field trial is
-// configured dynamically and is retrieved automatically by Chrome during
-// the startup.
-const char kAutocompleteDynamicFieldTrialPrefix[] = "AutocompleteDynamicTrial_";
-// The maximum number of the autocomplete dynamic field trials (aka layers).
-const int kMaxAutocompleteDynamicFieldTrials = 5;
-
-
-// Concatenates the autocomplete dynamic field trial prefix with a field trial
-// ID to form a complete autocomplete field trial name.
-std::string DynamicFieldTrialName(int id) {
-  return base::StringPrintf("%s%d", kAutocompleteDynamicFieldTrialPrefix, id);
-}
-
 void InitializeBucketsFromString(const std::string& bucket_string,
                                  ScoreBuckets* score_buckets) {
   // Clear the buckets.
   score_buckets->buckets().clear();
   base::StringPairs kv_pairs;
   if (base::SplitStringIntoKeyValuePairs(bucket_string, ':', ',', &kv_pairs)) {
     for (base::StringPairs::const_iterator it = kv_pairs.begin();
          it != kv_pairs.end(); ++it) {
       ScoreBuckets::CountMaxRelevance bucket;
       base::StringToDouble(it->first, &bucket.first);
@@ skipping 57 matching lines @@
   double time_ms;
   if ((half_life_days_ <= 0) ||
       ((time_ms = elapsed_time.InMillisecondsF()) <= 0))
     return 1.0;
 
   const double half_life_intervals =
       time_ms / base::TimeDelta::FromDays(half_life_days_).InMillisecondsF();
   return pow(2.0, -half_life_intervals);
 }
 
-void OmniboxFieldTrial::ActivateDynamicTrials() {
-  // Initialize all autocomplete dynamic field trials.  This method may be
-  // called multiple times.
-  for (int i = 0; i < kMaxAutocompleteDynamicFieldTrials; ++i)
-    base::FieldTrialList::FindValue(DynamicFieldTrialName(i));
-}
-
 int OmniboxFieldTrial::GetDisabledProviderTypes() {
   const std::string& types_string = variations::GetVariationParamValue(
       kBundledExperimentFieldTrialName,
       kDisableProvidersRule);
   int types = 0;
   if (types_string.empty() || !base::StringToInt(types_string, &types)) {
     return 0;
   }
   return types;
 }
 
 void OmniboxFieldTrial::GetActiveSuggestFieldTrialHashes(
     std::vector<uint32_t>* field_trial_hashes) {
   field_trial_hashes->clear();
-  for (int i = 0; i < kMaxAutocompleteDynamicFieldTrials; ++i) {
-    const std::string& trial_name = DynamicFieldTrialName(i);
-    if (base::FieldTrialList::TrialExists(trial_name))
-      field_trial_hashes->push_back(metrics::HashName(trial_name));
-  }
   if (base::FieldTrialList::TrialExists(kBundledExperimentFieldTrialName)) {
     field_trial_hashes->push_back(
         metrics::HashName(kBundledExperimentFieldTrialName));
   }
 }
 
 base::TimeDelta OmniboxFieldTrial::StopTimerFieldTrialDuration() {
   int stop_timer_ms;
   if (base::StringToInt(
       base::FieldTrialList::FindFullName(kStopTimerFieldTrialName),
@@ skipping 478 matching lines @@
   if (it != params.end())
     return it->second;
   // Fall back to the global instant extended context.
   it = params.find(rule + ":" + page_classification_str + ":*");
   if (it != params.end())
     return it->second;
   // Look up rule in the global context.
   it = params.find(rule + ":*:*");
   return (it != params.end()) ? it->second : std::string();
 }