See http://codereview.chromium.org/7337007.

This is a continuation with a fix for the failing tests.

BUG=90745,90837
TEST=none


Review URL: http://codereview.chromium.org/7465051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@94537 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 213 insertions, 15 deletions

diff --git a/chrome/browser/autocomplete/autocomplete.cc b/chrome/browser/autocomplete/autocomplete.cc
index 48e7dd6..6a87b83 100644
--- a/chrome/browser/autocomplete/autocomplete.cc
+++ b/chrome/browser/autocomplete/autocomplete.cc
@@ -25,6 +25,7 @@
 #include "chrome/browser/autocomplete/shortcuts_provider.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
+#include "chrome/browser/instant/instant_field_trial.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
@@ -793,7 +794,8 @@ AutocompleteController::AutocompleteController(
     AutocompleteControllerDelegate* delegate)
     : delegate_(delegate),
       done_(true),
-      in_start_(false) {
+      in_start_(false),
+      profile_(profile) {
   search_provider_ = new SearchProvider(this, profile);
   providers_.push_back(search_provider_);
   // TODO(mrossetti): Remove the following and permanently modify the
@@ -839,6 +841,7 @@ void AutocompleteController::SetProfile(Profile* profile) {
     (*i)->SetProfile(profile);
   input_.Clear();  // Ensure we don't try to do a "minimal_changes" query on a
                    // different profile.
+  profile_ = profile;
 }
 
 void AutocompleteController::Start(
@@ -880,7 +883,9 @@ void AutocompleteController::Start(
   if (matches_requested == AutocompleteInput::ALL_MATCHES &&
       (text.length() < 6)) {
     base::TimeTicks end_time = base::TimeTicks::Now();
-    std::string name = "Omnibox.QueryTime." + base::IntToString(text.length());
+    std::string name = "Omnibox.QueryTime." +
+                       InstantFieldTrial::GetGroupName(profile_) +
+                       base::IntToString(text.length());
     base::Histogram* counter = base::Histogram::FactoryGet(
         name, 1, 1000, 50, base::Histogram::kUmaTargetedHistogramFlag);
     counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
diff --git a/chrome/browser/autocomplete/autocomplete.h b/chrome/browser/autocomplete/autocomplete.h
index 2a19545..487e8bc 100644
--- a/chrome/browser/autocomplete/autocomplete.h
+++ b/chrome/browser/autocomplete/autocomplete.h
@@ -599,13 +599,14 @@ class AutocompleteController : public ACProviderListener {
   AutocompleteController(Profile* profile,
                          AutocompleteControllerDelegate* delegate);
 #ifdef UNIT_TEST
-  explicit AutocompleteController(const ACProviders& providers)
+  AutocompleteController(const ACProviders& providers, Profile* profile)
       : delegate_(NULL),
         providers_(providers),
         keyword_provider_(NULL),
         search_provider_(NULL),
         done_(true),
-        in_start_(false) {
+        in_start_(false),
+        profile_(profile) {
   }
 #endif
   ~AutocompleteController();
@@ -728,6 +729,8 @@ class AutocompleteController : public ACProviderListener {
   // notifications until Start() has been invoked on all providers.
   bool in_start_;
 
+  Profile* profile_;
+
   DISALLOW_COPY_AND_ASSIGN(AutocompleteController);
 };
 
diff --git a/chrome/browser/autocomplete/autocomplete_unittest.cc b/chrome/browser/autocomplete/autocomplete_unittest.cc
index 2b2a17b..be819c7 100644
--- a/chrome/browser/autocomplete/autocomplete_unittest.cc
+++ b/chrome/browser/autocomplete/autocomplete_unittest.cc
@@ -153,7 +153,8 @@ void AutocompleteProviderTest::ResetControllerWithTestProviders(
   providers_.push_back(providerB);
 
   // Reset the controller to contain our new providers.
-  AutocompleteController* controller = new AutocompleteController(providers_);
+  AutocompleteController* controller =
+      new AutocompleteController(providers_, &profile_);
   controller_.reset(controller);
   providerA->set_listener(controller);
   providerB->set_listener(controller);
@@ -201,7 +202,8 @@ void AutocompleteProviderTest::
   search_provider->AddRef();
   providers_.push_back(search_provider);
 
-  AutocompleteController* controller = new AutocompleteController(providers_);
+  AutocompleteController* controller =
+      new AutocompleteController(providers_, &profile_);
   controller_.reset(controller);
 }
 
diff --git a/chrome/browser/autocomplete/search_provider_unittest.cc b/chrome/browser/autocomplete/search_provider_unittest.cc
index 1de0d8f..7a2da19 100644
--- a/chrome/browser/autocomplete/search_provider_unittest.cc
+++ b/chrome/browser/autocomplete/search_provider_unittest.cc
@@ -153,6 +153,10 @@ void SearchProviderTest::SetUp() {
   provider_ = new SearchProvider(this, &profile_);
 
   URLFetcher::set_factory(&test_factory_);
+
+  // Prevent the Instant field trial from kicking in.
+  PrefService* service = profile_.GetPrefs();
+  service->SetBoolean(prefs::kInstantEnabledOnce, true);
 }
 
 void SearchProviderTest::OnProviderUpdate(bool updated_matches) {
@@ -623,7 +627,7 @@ TEST_F(SearchProviderTest, UpdateKeywordDescriptions) {
   ACProviders providers;
   SearchProvider* provider = provider_.release();
   providers.push_back(provider);
-  AutocompleteController controller(providers);
+  AutocompleteController controller(providers, &profile_);
   controller.set_search_provider(provider);
   provider->set_listener(&controller);
   controller.Start(ASCIIToUTF16("k t"), string16(), false, false, true,
diff --git a/chrome/browser/browser_main.cc b/chrome/browser/browser_main.cc
index f798e6d..d53fdd6 100644
--- a/chrome/browser/browser_main.cc
+++ b/chrome/browser/browser_main.cc
@@ -44,6 +44,7 @@
 #include "chrome/browser/first_run/first_run.h"
 #include "chrome/browser/first_run/first_run_browser_process.h"
 #include "chrome/browser/first_run/upgrade_util.h"
+#include "chrome/browser/instant/instant_field_trial.h"
 #include "chrome/browser/jankometer.h"
 #include "chrome/browser/language_usage_metrics.h"
 #include "chrome/browser/metrics/field_trial_synchronizer.h"
@@ -645,6 +646,7 @@ void BrowserMainParts::SetupFieldTrials(bool metrics_recording_enabled,
   if (!proxy_policy_is_set)
     ProxyConnectionsFieldTrial();
   prerender::ConfigurePrefetchAndPrerender(parsed_command_line());
+  InstantFieldTrial::Activate();
   SpdyFieldTrial();
   ConnectBackupJobsFieldTrial();
   WarmConnectionFieldTrial();
diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index 4e99b3d..2c5a59c 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -7,9 +7,11 @@
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
+#include "base/rand_util.h"
 #include "build/build_config.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/instant/instant_delegate.h"
+#include "chrome/browser/instant/instant_field_trial.h"
 #include "chrome/browser/instant/instant_loader.h"
 #include "chrome/browser/instant/instant_loader_manager.h"
 #include "chrome/browser/instant/promo_counter.h"
@@ -49,9 +51,10 @@ InstantController::InstantController(Profile* profile,
       last_transition_type_(PageTransition::LINK),
       ALLOW_THIS_IN_INITIALIZER_LIST(destroy_factory_(this)) {
   PrefService* service = profile->GetPrefs();
-  if (service) {
-    // kInstantWasEnabledOnce was added after instant, set it now to make sure
-    // it is correctly set.
+  if (service &&
+      InstantFieldTrial::GetGroup(profile) == InstantFieldTrial::INACTIVE) {
+    // kInstantEnabledOnce was added after instant, set it now to make sure it
+    // is correctly set.
     service->SetBoolean(prefs::kInstantEnabledOnce, true);
   }
 }
@@ -73,6 +76,9 @@ void InstantController::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterInt64Pref(prefs::kInstantEnabledTime,
                            false,
                            PrefService::UNSYNCABLE_PREF);
+  prefs->RegisterIntegerPref(prefs::kInstantFieldTrialRandomDraw,
+                             base::RandInt(0, 9999),
+                             PrefService::UNSYNCABLE_PREF);
   PromoCounter::RegisterUserPrefs(prefs, prefs::kInstantPromo);
 }
 
@@ -100,7 +106,8 @@ void InstantController::RecordMetrics(Profile* profile) {
 // static
 bool InstantController::IsEnabled(Profile* profile) {
   PrefService* prefs = profile->GetPrefs();
-  return prefs->GetBoolean(prefs::kInstantEnabled);
+  return prefs->GetBoolean(prefs::kInstantEnabled) ||
+         InstantFieldTrial::IsExperimentGroup(profile);
 }
 
 // static
@@ -113,11 +120,11 @@ void InstantController::Enable(Profile* profile) {
   if (!service)
     return;
 
+  service->SetBoolean(prefs::kInstantEnabledOnce, true);
   service->SetBoolean(prefs::kInstantEnabled, true);
   service->SetBoolean(prefs::kInstantConfirmDialogShown, true);
   service->SetInt64(prefs::kInstantEnabledTime,
                     base::Time::Now().ToInternalValue());
-  service->SetBoolean(prefs::kInstantEnabledOnce, true);
 }
 
 // static
@@ -135,6 +142,12 @@ void InstantController::Disable(Profile* profile) {
                                 delta.InMinutes(), 1, 60 * 24 * 10, 50);
   }
 
+  if (InstantFieldTrial::IsExperimentGroup(profile)) {
+    UMA_HISTOGRAM_COUNTS(
+        "Instant.FieldTrialOptOut." + InstantFieldTrial::GetGroupName(profile),
+        1);
+  }
+
   service->SetBoolean(prefs::kInstantEnabledOnce, true);
   service->SetBoolean(prefs::kInstantEnabled, false);
 }
@@ -377,8 +390,10 @@ void InstantController::OnAutocompleteLostFocus(
 void InstantController::OnAutocompleteGotFocus(
     TabContentsWrapper* tab_contents) {
   CommandLine* cl = CommandLine::ForCurrentProcess();
-  if (!cl->HasSwitch(switches::kPreloadInstantSearch))
+  if (!cl->HasSwitch(switches::kPreloadInstantSearch) &&
+      !InstantFieldTrial::IsExperimentGroup(tab_contents->profile())) {
     return;
+  }
 
   if (is_active_)
     return;
@@ -389,7 +404,7 @@ void InstantController::OnAutocompleteGotFocus(
     return;
 
   const TemplateURL* template_url = model->GetDefaultSearchProvider();
-  if (!template_url || !template_url->instant_url())
+  if (!template_url || !template_url->instant_url() || !template_url->id())
     return;
 
   if (tab_contents != tab_contents_)
@@ -705,7 +720,8 @@ InstantController::PreviewCondition InstantController::GetPreviewConditionFor(
     return PREVIEW_CONDITION_BLACKLISTED;
 
   const CommandLine* cl = CommandLine::ForCurrentProcess();
-  if (cl->HasSwitch(switches::kRestrictInstantToSearch) &&
+  if ((cl->HasSwitch(switches::kRestrictInstantToSearch) ||
+       InstantFieldTrial::IsExperimentGroup(tab_contents_->profile())) &&
       match.type != AutocompleteMatch::SEARCH_WHAT_YOU_TYPED &&
       match.type != AutocompleteMatch::SEARCH_HISTORY &&
       match.type != AutocompleteMatch::SEARCH_SUGGEST &&
diff --git a/chrome/browser/instant/instant_field_trial.cc b/chrome/browser/instant/instant_field_trial.cc
new file mode 100644
index 0000000..2c3e63d
--- /dev/null
+++ b/chrome/browser/instant/instant_field_trial.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2011 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/instant/instant_field_trial.h"
+
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+
+namespace {
+bool field_trial_active_ = false;
+}
+
+// static
+void InstantFieldTrial::Activate() {
+  field_trial_active_ = true;
+}
+
+// static
+InstantFieldTrial::Group InstantFieldTrial::GetGroup(Profile* profile) {
+  if (!field_trial_active_)
+    return INACTIVE;
+
+  if (profile->IsOffTheRecord())
+    return INACTIVE;
+
+  const PrefService* prefs = profile->GetPrefs();
+  if (!prefs ||
+      prefs->GetBoolean(prefs::kInstantEnabledOnce) ||
+      prefs->IsManagedPreference(prefs::kInstantEnabled)) {
+    return INACTIVE;
+  }
+
+  const int random = prefs->GetInteger(prefs::kInstantFieldTrialRandomDraw);
+  return random < 4500 ? CONTROL1 :    // 45%
+         random < 9000 ? CONTROL2 :    // 45%
+         random < 9500 ? EXPERIMENT1   //  5%
+                       : EXPERIMENT2;  //  5%
+}
+
+// static
+bool InstantFieldTrial::IsExperimentGroup(Profile* profile) {
+  Group group = GetGroup(profile);
+  return group == EXPERIMENT1 || group == EXPERIMENT2;
+}
+
+// static
+std::string InstantFieldTrial::GetGroupName(Profile* profile) {
+  switch (GetGroup(profile)) {
+    case INACTIVE:    return "InstantInactive";
+    case CONTROL1:    return "InstantControl1";
+    case CONTROL2:    return "InstantControl2";
+    case EXPERIMENT1: return "InstantExperiment1";
+    case EXPERIMENT2: return "InstantExperiment2";
+  }
+  NOTREACHED();
+  return "InstantUnknown";
+}
diff --git a/chrome/browser/instant/instant_field_trial.h b/chrome/browser/instant/instant_field_trial.h
new file mode 100644
index 0000000..fd808f6
--- /dev/null
+++ b/chrome/browser/instant/instant_field_trial.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2011 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.
+
+#ifndef CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_
+#define CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+
+class Profile;
+
+// This class manages the Instant field trial. Each user is in exactly one of
+// two field trial groups: Control or Experiment.
+// - Control and Experiment are all the other users, i.e., those who have never
+//   touched the Preferences option. Some percentage of these users are chosen
+//   into the Experiment group and get Instant enabled automatically. The rest
+//   fall into the Control group; for them, Instant remains disabled by default.
+// - Control and Experiment are further split into two subgroups each, in order
+//   to detect bias between them (when analyzing metrics). The subgroups are
+//   treated identically for all other purposes.
+//
+// There is a possibility that the field trial is not active.
+// - Inactive users are those who have played with the Instant option in the
+//   Preferences page, or those for whom group policy provides an override, or
+//   those with an incognito profile, etc. The field trial is inactive for such
+//   users, so their Instant preference setting is respected. The field trial is
+//   initially inactive so testing is not affected by the field trial.
+class InstantFieldTrial {
+ public:
+  enum Group {
+    INACTIVE,
+    CONTROL1,
+    CONTROL2,
+    EXPERIMENT1,
+    EXPERIMENT2,
+  };
+
+  // Activate the field trial. Before this call, all calls to GetGroup will
+  // return INACTIVE.
+  static void Activate();
+
+  // Return the field trial group this profile belongs to.
+  static Group GetGroup(Profile* profile);
+
+  // Check if the group is either of the two experiment subgroups.
+  static bool IsExperimentGroup(Profile* profile);
+
+  // Returns a string describing the user's group. Can be added to histogram
+  // names, to split histograms by field trial groups.
+  static std::string GetGroupName(Profile* profile);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(InstantFieldTrial);
+};
+
+#endif  // CHROME_BROWSER_INSTANT_INSTANT_FIELD_TRIAL_H_
diff --git a/chrome/browser/resources/options/browser_options.html b/chrome/browser/resources/options/browser_options.html
index d03df9b..e23b0b8 100644
--- a/chrome/browser/resources/options/browser_options.html
+++ b/chrome/browser/resources/options/browser_options.html
@@ -94,6 +94,8 @@
           <div id="instantOption" class="checkbox">
             <label>
               <!-- TODO(estade): metric? -->
+              <input id="instantFieldTrialCheckbox" type="checkbox"
+                  checked="checked" hidden>
               <input id="instantEnabledCheckbox" type="checkbox"
                   pref="instant.enabled">
               <span i18n-content="instantName"></span>
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index ffd838e..e8b46fb 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -83,9 +83,18 @@ cr.define('options', function() {
         return true;
       };
 
+      $('instantFieldTrialCheckbox').addEventListener('change',
+          function(event) {
+            this.checked = true;
+            chrome.send('disableInstant');
+          });
+
       Preferences.getInstance().addEventListener('instant.confirm_dialog_shown',
           this.onInstantConfirmDialogShownChanged_.bind(this));
 
+      Preferences.getInstance().addEventListener('instant.enabled',
+          this.onInstantEnabledChanged_.bind(this));
+
       var homepageField = $('homepageURL');
       $('homepageUseNTPButton').onchange =
           this.handleHomepageUseNTPButtonChange_.bind(this);
@@ -169,6 +178,26 @@ cr.define('options', function() {
     },
 
     /**
+     * Called when the value of the instant.enabled preference changes. Request
+     * the state of the Instant field trial experiment.
+     * @param {Event} event Change event.
+     * @private
+     */
+    onInstantEnabledChanged_: function(event) {
+      chrome.send('getInstantFieldTrialStatus');
+    },
+
+    /**
+     * Called to set the Instant field trial status.
+     * @param {boolean} enabled If true, the experiment is enabled.
+     * @private
+     */
+    setInstantFieldTrialStatus_: function(enabled) {
+      $('instantEnabledCheckbox').hidden = enabled;
+      $('instantFieldTrialCheckbox').hidden = !enabled;
+    },
+
+    /**
      * Update the Default Browsers section based on the current state.
      * @param {string} statusString Description of the current default state.
      * @param {boolean} isDefault Whether or not the browser is currently
@@ -489,6 +518,10 @@ cr.define('options', function() {
     BrowserOptions.getInstance().updateAutocompleteSuggestions_(suggestions);
   };
 
+  BrowserOptions.setInstantFieldTrialStatus = function(enabled) {
+    BrowserOptions.getInstance().setInstantFieldTrialStatus_(enabled);
+  };
+
   // Export
   return {
     BrowserOptions: BrowserOptions
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.cc b/chrome/browser/ui/webui/options/browser_options_handler.cc
index 622b6e01..9a541ee 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/custom_home_pages_table_model.h"
 #include "chrome/browser/instant/instant_confirm_dialog.h"
 #include "chrome/browser/instant/instant_controller.h"
+#include "chrome/browser/instant/instant_field_trial.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
@@ -129,6 +130,9 @@ void BrowserOptionsHandler::RegisterMessages() {
   web_ui_->RegisterMessageCallback(
       "disableInstant",
       NewCallback(this, &BrowserOptionsHandler::DisableInstant));
+  web_ui_->RegisterMessageCallback(
+      "getInstantFieldTrialStatus",
+      NewCallback(this, &BrowserOptionsHandler::GetInstantFieldTrialStatus));
 }
 
 void BrowserOptionsHandler::Initialize() {
@@ -484,6 +488,13 @@ void BrowserOptionsHandler::DisableInstant(const ListValue* args) {
   InstantController::Disable(web_ui_->GetProfile());
 }
 
+void BrowserOptionsHandler::GetInstantFieldTrialStatus(const ListValue* args) {
+  FundamentalValue enabled(
+      InstantFieldTrial::IsExperimentGroup(web_ui_->GetProfile()));
+  web_ui_->CallJavascriptFunction("BrowserOptions.setInstantFieldTrialStatus",
+                                  enabled);
+}
+
 void BrowserOptionsHandler::OnResultChanged(bool default_match_changed) {
   const AutocompleteResult& result = autocomplete_controller_->result();
   ListValue suggestions;
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.h b/chrome/browser/ui/webui/options/browser_options_handler.h
index e400130..edef235 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.h
+++ b/chrome/browser/ui/webui/options/browser_options_handler.h
@@ -94,6 +94,9 @@ class BrowserOptionsHandler : public OptionsPageUIHandler,
   void EnableInstant(const ListValue* args);
   void DisableInstant(const ListValue* args);
 
+  // Called to request information about the Instant field trial.
+  void GetInstantFieldTrialStatus(const ListValue* args);
+
   // Returns the string ID for the given default browser state.
   int StatusStringIdForState(ShellIntegration::DefaultWebClientState state);