[Cleanup] Remove some expired omnibox field trials.

BUG=none
TEST=none
R=mpearson@chromium.org

Review URL: https://codereview.chromium.org/1584733003

Cr-Commit-Position: refs/heads/master@{#370734}

chrome/browser/autocomplete/search_provider_unittest.cc

@@ -549,10 +549,8 @@ void SearchProviderTest::ResetFieldTrialList() {
   field_trial_list_.reset(new base::FieldTrialList(
       new metrics::SHA1EntropyProvider("foo")));
   variations::testing::ClearAllVariationParams();
-  base::FieldTrial* trial = base::FieldTrialList::CreateFieldTrial(
-      "AutocompleteDynamicTrial_0", "DefaultGroup");
-  trial->group();
 }
+
 base::FieldTrial* SearchProviderTest::CreateFieldTrial(
     const char* field_trial_rule,
     bool enabled) {
@@ -2550,6 +2548,10 @@ TEST_F(SearchProviderTest, DefaultProviderSuggestRelevanceScoringUrlInput) {
 
 // A basic test that verifies the field trial triggered parsing logic.
 TEST_F(SearchProviderTest, FieldTrialTriggeredParsing) {
+  base::FieldTrial* trial = base::FieldTrialList::CreateFieldTrial(
+      OmniboxFieldTrial::kBundledExperimentFieldTrialName, "DefaultGroup");
+  trial->group();
+
   QueryForInputAndWaitForFetcherResponses(
       ASCIIToUTF16("foo"), false,
       "[\"foo\",[\"foo bar\"],[\"\"],[],"

chrome/browser/chrome_browser_field_trials.cc

@@ -13,7 +13,6 @@
 #include "build/build_config.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/metrics/metrics_pref_names.h"
-#include "components/omnibox/browser/omnibox_field_trial.h"
 
 #if defined(OS_ANDROID) || defined(OS_IOS)
 #include "chrome/browser/chrome_browser_field_trials_mobile.h"
@@ -44,6 +43,4 @@ void ChromeBrowserFieldTrials::InstantiateDynamicTrials() {
   // The following trials are used from renderer process.
   // Mark here so they will be sync-ed.
   base::FieldTrialList::FindValue("DisplayList2dCanvas");
-  // Activate the autocomplete dynamic field trials.
-  OmniboxFieldTrial::ActivateDynamicTrials();
 }

components/omnibox/browser/omnibox_field_trial.cc

@@ -12,7 +12,6 @@
 #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"
@@ -32,20 +31,6 @@ 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.
@@ -123,13 +108,6 @@ double HUPScoringParams::ScoreBuckets::HalfLifeTimeDecay(
   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,
@@ -144,11 +122,6 @@ int OmniboxFieldTrial::GetDisabledProviderTypes() {
 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));

components/omnibox/browser/omnibox_field_trial.h

@@ -111,14 +111,6 @@ class OmniboxFieldTrial {
     EMPHASIZE_NEVER = 3
   };
 
-  // Activates all dynamic field trials.  The main difference between
-  // the autocomplete dynamic and static field trials is that the former
-  // don't require any code changes on the Chrome side as they are controlled
-  // on the server side.  Chrome binary simply propagates all necessary
-  // information through the X-Client-Data header.
-  // This method may be called multiple times.
-  static void ActivateDynamicTrials();
-
   // ---------------------------------------------------------
   // For any experiment that's part of the bundled omnibox field trial.
 

components/omnibox/browser/omnibox_field_trial_unittest.cc

@@ -31,7 +31,6 @@ class OmniboxFieldTrialTest : public testing::Test {
     field_trial_list_.reset(new base::FieldTrialList(
         new metrics::SHA1EntropyProvider("foo")));
     variations::testing::ClearAllVariationParams();
-    OmniboxFieldTrial::ActivateDynamicTrials();
   }
 
   // Creates and activates a field trial.
@@ -138,12 +137,6 @@ void OmniboxFieldTrialTest::VerifySuggestPollingStrategy(
 TEST_F(OmniboxFieldTrialTest, GetDisabledProviderTypes) {
   EXPECT_EQ(0, OmniboxFieldTrial::GetDisabledProviderTypes());
 
-  {
-    SCOPED_TRACE("Outside the bundled field trial.");
-    CreateTestTrial("AutocompleteDynamicTrial_0", "DisabledProviders_123");
-    EXPECT_EQ(0, OmniboxFieldTrial::GetDisabledProviderTypes());
-  }
-
   {
     SCOPED_TRACE("Valid field trial, missing param.");
     ResetFieldTrialList();

ios/chrome/browser/ios_chrome_field_trials.cc

@@ -5,23 +5,9 @@
 #include "ios/chrome/browser/ios_chrome_field_trials.h"
 
 #include "base/metrics/field_trial.h"
-#include "components/omnibox/browser/omnibox_field_trial.h"
-
-namespace {
-
-// Instantiates dynamic field trials by querying their state to ensure they
-// get reported as used.
-void InstantiateDynamicTrials() {
-  // Activate the autocomplete dynamic field trials.
-  OmniboxFieldTrial::ActivateDynamicTrials();
-
-  // Activate the iOS tab eviction dynamic field trials.
-  base::FieldTrialList::FindValue("TabEviction");
-}
-
-}  // namespace
 
 void SetupFieldTrials(const base::CommandLine& command_line,
                       const base::Time& install_time) {
-  InstantiateDynamicTrials();
+  // Activate the iOS tab eviction dynamic field trials.
+  base::FieldTrialList::FindValue("TabEviction");
 }