Add possibility to divide chrome users into groups of equal size, and change promo code to reflect sync promo.

BUG=68671, 68672
TEST=none
Review URL: http://codereview.chromium.org/6313009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72374 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 206 insertions, 60 deletions

diff --git a/chrome/browser/dom_ui/ntp_resource_cache.cc b/chrome/browser/dom_ui/ntp_resource_cache.cc
index b82cf3c..b57fb98 100644
--- a/chrome/browser/dom_ui/ntp_resource_cache.cc
+++ b/chrome/browser/dom_ui/ntp_resource_cache.cc
@@ -337,6 +337,8 @@ void NTPResourceCache::CreateNewTabHTML() {
       l10n_util::GetStringUTF16(IDS_APPS_PROMO_TEXT_1));
   localized_strings.SetString("appspromotext2",
       l10n_util::GetStringUTF16(IDS_APPS_PROMO_TEXT_2));
+  localized_strings.SetString("syncpromotext",
+      l10n_util::GetStringUTF16(IDS_SYNC_START_SYNC_BUTTON_LABEL));
 #if defined(OS_CHROMEOS)
   localized_strings.SetString("expandMenu",
       l10n_util::GetStringUTF16(IDS_NEW_TAB_CLOSE_MENU_EXPAND));
diff --git a/chrome/browser/resources/new_new_tab.html b/chrome/browser/resources/new_new_tab.html
index b0f8ae9..ded221f 100644
--- a/chrome/browser/resources/new_new_tab.html
+++ b/chrome/browser/resources/new_new_tab.html
@@ -136,7 +136,10 @@ if ('mode' in hashParams) {
   <div id="notification-container">
     <div id="notification">
       <span>&nbsp;</span>
-      <span class="link"><span class="link-color"></span></span>
+      <span class="link"><span class="link-color" id="action-link"></span>
+      </span>
+      <span class="link"><span class="link-color" id="close-link"></span>
+      </span>
     </div>
   </div>
 
diff --git a/chrome/browser/resources/new_new_tab.js b/chrome/browser/resources/new_new_tab.js
index fdc1c61..c6520c0 100644
--- a/chrome/browser/resources/new_new_tab.js
+++ b/chrome/browser/resources/new_new_tab.js
@@ -807,7 +807,7 @@ function syncMessageChanged(newMessage) {
 }
 
 /**
- * Invoked when the link in the sync status section is clicked.
+ * Invoked when the link in the sync promo or sync status section is clicked.
  */
 function syncSectionLinkClicked(e) {
   chrome.send('SyncLinkClicked');
@@ -935,9 +935,11 @@ var notificationTimeout;
  * @param {function=} opt_f Function to call when the user clicks the action
  *                          link.
  * @param {number=} opt_delay The time in milliseconds before hiding the
- * i                          notification.
+ *                            notification.
+ * @param {boolean=} close If true, show a close link next to the notification.
  */
-function showNotification(message, actionText, opt_f, opt_delay) {
+function showNotification(message, actionText, opt_f, opt_delay, opt_close) {
+// TODO(arv): Create a notification component.
   var notificationElement = $('notification');
   var f = opt_f || function() {};
   var delay = opt_delay || 10000;
@@ -957,12 +959,26 @@ function showNotification(message, actionText, opt_f, opt_delay) {
     hideNotification();
   }
 
+  function closeNotification() {
+    chrome.send('closePromo');
+    hideNotification();
+  }
+
   // Remove classList entries from previous notifications.
   notification.classList.remove('first-run');
   notification.classList.remove('promo');
 
   var messageContainer = notificationElement.firstElementChild;
-  var actionLink = notificationElement.querySelector('.link-color');
+  var actionLink = notificationElement.querySelector('#action-link');
+
+  if (opt_close) {
+    var closeLink = notificationElement.querySelector('#close-link');
+    closeLink.textContent =
+        localStrings.getString('closefirstrunnotification');
+    closeLink.onclick = closeNotification;
+    closeLink.onkeydown = handleIfEnterKey(closeNotification);
+    closeLink.tabIndex = 1;
+  }
 
   if (typeof message == 'string') {
     messageContainer.textContent = message;
@@ -993,14 +1009,17 @@ function hideNotification() {
   var notificationElement = $('notification');
   notificationElement.classList.remove('show');
   document.body.classList.remove('notification-shown');
-  var actionLink = notificationElement.querySelector('.link-color');
+  var actionLink = notificationElement.querySelector('#actionlink');
+  var closeLink = notificationElement.querySelector('#closelink');
   // Prevent tabbing to the hidden link.
   actionLink.tabIndex = -1;
+  closeLink.tabIndex = -1;
   // Setting tabIndex to -1 only prevents future tabbing to it. If, however, the
   // user switches window or a tab and then moves back to this tab the element
   // may gain focus. We therefore make sure that we blur the element so that the
   // element focus is not restored when coming back to this window.
   actionLink.blur();
+  closeLink.blur();
 }
 
 function showFirstRunNotification() {
@@ -1013,9 +1032,10 @@ function showFirstRunNotification() {
 
 function showPromoNotification() {
   showNotification(parseHtmlSubset(localStrings.getString('serverpromo')),
-                   localStrings.getString('closefirstrunnotification'),
-                   function () { chrome.send('closePromo'); },
-                   60000);
+                   localStrings.getString('syncpromotext'),
+                   function () { chrome.send('SyncLinkClicked'); },
+                   60000,
+                   true);
   var notificationElement = $('notification');
   notification.classList.add('promo');
 }
diff --git a/chrome/browser/sessions/session_service.h b/chrome/browser/sessions/session_service.h
index f17b77a..df97a78 100644
--- a/chrome/browser/sessions/session_service.h
+++ b/chrome/browser/sessions/session_service.h
@@ -444,7 +444,7 @@ class SessionService : public BaseSessionService,
   // current/previous session.
   bool move_on_new_browser_;
 
-  // Used for reporting frequency of session alteriing operations.
+  // Used for reporting frequency of session altering operations.
   base::TimeTicks last_updated_tab_closed_time_;
   base::TimeTicks last_updated_nav_list_pruned_time_;
   base::TimeTicks last_updated_nav_entry_commit_time_;
diff --git a/chrome/browser/web_resource/web_resource_service.cc b/chrome/browser/web_resource/web_resource_service.cc
index 35f4aea..f7984a7 100644
--- a/chrome/browser/web_resource/web_resource_service.cc
+++ b/chrome/browser/web_resource/web_resource_service.cc
@@ -4,6 +4,8 @@
 
 #include "chrome/browser/web_resource/web_resource_service.h"
 
+#include <string>
+
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/string_util.h"
@@ -14,6 +16,7 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/platform_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/sync_ui_util.h"
 #include "chrome/common/chrome_switches.h"
@@ -34,6 +37,21 @@ static const int kStartResourceFetchDelay = 5000;
 // Delay between calls to update the cache (48 hours).
 static const int kCacheUpdateDelay = 48 * 60 * 60 * 1000;
 
+// Users are randomly assigned to one of kNTPPromoGroupSize buckets, in order
+// to be able to roll out promos slowly, or display different promos to
+// different groups.
+static const int kNTPPromoGroupSize = 16;
+
+// Maximum number of hours for each time slice (4 weeks).
+static const int kMaxTimeSliceHours = 24 * 7 * 4;
+
+// Used to determine which build type should be shown a given promo.
+enum BuildType {
+  DEV_BUILD = 1,
+  BETA_BUILD = 1 << 1,
+  STABLE_BUILD = 1 << 2,
+};
+
 }  // namespace
 
 const char* WebResourceService::kCurrentTipPrefName = "current_tip";
@@ -203,7 +221,8 @@ class WebResourceService::UnpackerClient
 // Server for dynamically loaded NTP HTML elements. TODO(mirandac): append
 // locale for future usage, when we're serving localizable strings.
 const char* WebResourceService::kDefaultWebResourceServer =
-    "https://www.google.com/support/chrome/bin/topic/30248/inproduct";
+//    "https://www.google.com/support/chrome/bin/topic/30248/inproduct";
+  "http://www.corp.google.com/~mirandac/testprefs.json";
 
 WebResourceService::WebResourceService(Profile* profile)
     : prefs_(profile->GetPrefs()),
@@ -227,6 +246,10 @@ void WebResourceService::Init() {
   prefs_->RegisterRealPref(prefs::kNTPPromoEnd, 0);
   prefs_->RegisterStringPref(prefs::kNTPPromoLine, std::string());
   prefs_->RegisterBooleanPref(prefs::kNTPPromoClosed, false);
+  prefs_->RegisterIntegerPref(prefs::kNTPPromoGroup, -1);
+  prefs_->RegisterIntegerPref(prefs::kNTPPromoBuild,
+                              DEV_BUILD | BETA_BUILD | STABLE_BUILD);
+  prefs_->RegisterIntegerPref(prefs::kNTPPromoGroupTimeSlice, 0);
 
   // If the promo start is in the future, set a notification task to invalidate
   // the NTP cache at the time of the promo start.
@@ -242,8 +265,7 @@ void WebResourceService::EndFetch() {
 void WebResourceService::OnWebResourceUnpacked(
   const DictionaryValue& parsed_json) {
   UnpackLogoSignal(parsed_json);
-  if (WebResourceServiceUtil::CanShowPromo(profile_))
-    UnpackPromoSignal(parsed_json);
+  UnpackPromoSignal(parsed_json);
   EndFetch();
 }
 
@@ -377,6 +399,9 @@ void WebResourceService::UnpackPromoSignal(const DictionaryValue& parsed_json) {
       std::string promo_start_string = "";
       std::string promo_end_string = "";
       std::string promo_string = "";
+      std::string promo_build = "";
+      int promo_build_type;
+      int time_slice_hrs;
       for (ListValue::const_iterator tip_iter = answer_list->begin();
            tip_iter != answer_list->end(); ++tip_iter) {
         if (!(*tip_iter)->IsType(Value::TYPE_DICTIONARY))
@@ -386,9 +411,33 @@ void WebResourceService::UnpackPromoSignal(const DictionaryValue& parsed_json) {
         std::string promo_signal;
         if (a_dic->GetString("name", &promo_signal)) {
           if (promo_signal == "promo_start") {
+            a_dic->GetString("question", &promo_build);
+            size_t split = promo_build.find(":");
+            if (split != std::string::npos &&
+                base::StringToInt(promo_build.substr(0, split),
+                                  &promo_build_type) &&
+                base::StringToInt(promo_build.substr(split+1),
+                                  &time_slice_hrs) &&
+                promo_build_type >= 0 &&
+                promo_build_type <= (DEV_BUILD | BETA_BUILD | STABLE_BUILD) &&
+                time_slice_hrs >= 0 &&
+                time_slice_hrs <= kMaxTimeSliceHours) {
+              prefs_->SetInteger(prefs::kNTPPromoBuild, promo_build_type);
+              prefs_->SetInteger(prefs::kNTPPromoGroupTimeSlice,
+                                 time_slice_hrs);
+            } else {
+              // If no time data or bad time data are set, show promo on all
+              // builds with no time slicing.
+              prefs_->SetInteger(prefs::kNTPPromoBuild,
+                                 DEV_BUILD | BETA_BUILD | STABLE_BUILD);
+              prefs_->SetInteger(prefs::kNTPPromoGroupTimeSlice, 0);
+            }
             a_dic->GetString("inproduct", &promo_start_string);
             a_dic->GetString("tooltip", &promo_string);
             prefs_->SetString(prefs::kNTPPromoLine, promo_string);
+            srand(static_cast<uint32>(time(NULL)));
+            prefs_->SetInteger(prefs::kNTPPromoGroup,
+                               rand() % kNTPPromoGroupSize);
           } else if (promo_signal == "promo_end") {
             a_dic->GetString("inproduct", &promo_end_string);
           }
@@ -404,7 +453,11 @@ void WebResourceService::UnpackPromoSignal(const DictionaryValue& parsed_json) {
                 ASCIIToWide(promo_start_string).c_str(), &start_time) &&
             base::Time::FromString(
                 ASCIIToWide(promo_end_string).c_str(), &end_time)) {
-          promo_start = start_time.ToDoubleT();
+          // Add group time slice, adjusted from hours to seconds.
+          promo_start = start_time.ToDoubleT() +
+              (prefs_->FindPreference(prefs::kNTPPromoGroup) ?
+                  prefs_->GetInteger(prefs::kNTPPromoGroup) *
+                      time_slice_hrs * 60 * 60 : 0);
           promo_end = end_time.ToDoubleT();
         }
       }
@@ -415,10 +468,12 @@ void WebResourceService::UnpackPromoSignal(const DictionaryValue& parsed_json) {
   // notification, so that the logo on the NTP is updated. This check is
   // outside the reading of the web resource data, because the absence of
   // dates counts as a triggering change if there were dates before.
+  // Also reset the promo closed preference, to signal a new promo.
   if (!(old_promo_start == promo_start) ||
       !(old_promo_end == promo_end)) {
     prefs_->SetReal(prefs::kNTPPromoStart, promo_start);
     prefs_->SetReal(prefs::kNTPPromoEnd, promo_end);
+    prefs_->SetBoolean(prefs::kNTPPromoClosed, false);
     ScheduleNotification(promo_start, promo_end);
   }
 }
@@ -498,32 +553,28 @@ bool CanShowPromo(Profile* profile) {
   if (prefs->HasPrefPath(prefs::kNTPPromoClosed))
     promo_closed = prefs->GetBoolean(prefs::kNTPPromoClosed);
 
-  bool has_extensions = false;
-  ExtensionService* extensions_service = profile->GetExtensionService();
-  if (extensions_service) {
-    const ExtensionList* extensions = extensions_service->extensions();
-    for (ExtensionList::const_iterator iter = extensions->begin();
-         iter != extensions->end();
-         ++iter) {
-      if ((*iter)->location() == Extension::INTERNAL) {
-        has_extensions = true;
-        break;
-      }
-    }
-  }
-
-  // Note that HasProfileSyncService() will be false for ChromeOS, so
-  // promo_options will only be true if the user has an extension installed.
-  // See http://crosbug/10209
-  bool promo_options =
+  // Only show if not synced.
+  bool is_synced =
       (profile->HasProfileSyncService() &&
           sync_ui_util::GetStatus(
-              profile->GetProfileSyncService()) == sync_ui_util::SYNCED) ||
-      has_extensions;
+              profile->GetProfileSyncService()) == sync_ui_util::SYNCED);
+
+  const std::string channel = platform_util::GetVersionStringModifier();
+  bool is_promo_build = false;
+  if (prefs->HasPrefPath(prefs::kNTPPromoBuild)) {
+    int builds_allowed = prefs->GetInteger(prefs::kNTPPromoBuild);
+    if (channel == "dev") {
+      is_promo_build = (DEV_BUILD & builds_allowed) != 0;
+    } else if (channel == "beta") {
+      is_promo_build = (BETA_BUILD & builds_allowed) != 0;
+    } else if (channel == "stable") {
+      is_promo_build = (STABLE_BUILD & builds_allowed) != 0;
+    } else {
+      is_promo_build = true;
+    }
+  }
 
-  return !promo_closed &&
-         promo_options &&
-         g_browser_process->GetApplicationLocale() == "en-US";
+  return !promo_closed && !is_synced && is_promo_build;
 }
 
 }  // namespace WebResourceService
diff --git a/chrome/browser/web_resource/web_resource_service.h b/chrome/browser/web_resource/web_resource_service.h
index 70c8000..2373757 100644
--- a/chrome/browser/web_resource/web_resource_service.h
+++ b/chrome/browser/web_resource/web_resource_service.h
@@ -23,6 +23,14 @@ bool CanShowPromo(Profile* profile);
 
 }  // namespace WebResourceService
 
+// A WebResourceService fetches data from a web resource server to be used to
+// dynamically change the appearance of the New Tab Page. For example, it has
+// been used to fetch "tips" to be displayed on the NTP, or to display
+// promotional messages to certain groups of Chrome users.
+//
+// TODO(mirandac): Arrange for a server to be set up specifically for promo
+// messages, which have until now been piggybacked onto the old tips server
+// structure. (see http://crbug.com/70634 for details.)
 class WebResourceService
     : public UtilityProcessHost::Client {
  public:
@@ -65,7 +73,7 @@ class WebResourceService
   //       {
   //         "answer_id": "1067976",
   //         "name": "promo_start",
-  //         "question": "",
+  //         "question": "1:24",
   //         "tooltip":
   //       "Click \u003ca href=http://www.google.com\u003ehere\u003c/a\u003e!",
   //         "inproduct": "10/8/09 12:00",
@@ -84,6 +92,18 @@ class WebResourceService
   //   }
   // }
   //
+  // Because the promo signal data is piggybacked onto the tip server, the
+  // values don't exactly correspond with the field names:
+  //
+  // For "promo_start" or "promo_end", the date to start or stop showing the
+  // promotional line is given by the "inproduct" line.
+  // For "promo_start", the promotional line itself is given in the "tooltip"
+  // field. The "question" field gives the type of builds that should be shown
+  // this promo (see the BuildType enum in web_resource_service.cc) and the
+  // number of hours that each promo group should see it, separated by ":".
+  // For example, "7:24" would indicate that all builds should see the promo,
+  // and each group should see it for 24 hours.
+  //
   // Public for unit testing.
   void UnpackPromoSignal(const DictionaryValue& parsed_json);
 
diff --git a/chrome/browser/web_resource/web_resource_service_unittest.cc b/chrome/browser/web_resource/web_resource_service_unittest.cc
index 2211bb4..4127a6e 100644
--- a/chrome/browser/web_resource/web_resource_service_unittest.cc
+++ b/chrome/browser/web_resource/web_resource_service_unittest.cc
@@ -14,6 +14,17 @@
 
 typedef testing::Test WebResourceServiceTest;
 
+namespace {
+
+// From web_resource_service.cc
+enum BuildType {
+  DEV_BUILD = 1,
+  BETA_BUILD = 1 << 1,
+  STABLE_BUILD = 1 << 2,
+};
+
+}  // namespace
+
 // Verifies that custom dates read from a web resource server are written to
 // the preferences file.
 TEST_F(WebResourceServiceTest, UnpackLogoSignal) {
@@ -42,12 +53,15 @@ TEST_F(WebResourceServiceTest, UnpackLogoSignal) {
 
   // Check that prefs are set correctly.
   web_resource_service->UnpackLogoSignal(*(test_json.get()));
+  PrefService* prefs = profile.GetPrefs();
+  ASSERT_TRUE(prefs != NULL);
+
   double logo_start =
-      profile.GetPrefs()->GetReal(prefs::kNTPCustomLogoStart);
-  ASSERT_EQ(logo_start, 1264899600);  // unix epoch for Jan 31 2010 0100 GMT.
+      prefs->GetReal(prefs::kNTPCustomLogoStart);
+  EXPECT_EQ(logo_start, 1264899600);  // unix epoch for Jan 31 2010 0100 GMT.
   double logo_end =
-      profile.GetPrefs()->GetReal(prefs::kNTPCustomLogoEnd);
-  ASSERT_EQ(logo_end, 1327971600);  // unix epoch for Jan 31 2012 0100 GMT.
+      prefs->GetReal(prefs::kNTPCustomLogoEnd);
+  EXPECT_EQ(logo_end, 1327971600);  // unix epoch for Jan 31 2012 0100 GMT.
 
   // Change the start only and recheck.
   json = "{ "
@@ -70,8 +84,9 @@ TEST_F(WebResourceServiceTest, UnpackLogoSignal) {
 
   // Check that prefs are set correctly.
   web_resource_service->UnpackLogoSignal(*(test_json.get()));
-  logo_start = profile.GetPrefs()->GetReal(prefs::kNTPCustomLogoStart);
-  ASSERT_EQ(logo_start, 1267365600);  // date changes to Feb 28 2010 1400 GMT.
+
+  logo_start = prefs->GetReal(prefs::kNTPCustomLogoStart);
+  EXPECT_EQ(logo_start, 1267365600);  // date changes to Feb 28 2010 1400 GMT.
 
   // If no date is included in the prefs, reset custom logo dates to 0.
   json = "{ "
@@ -88,10 +103,10 @@ TEST_F(WebResourceServiceTest, UnpackLogoSignal) {
 
   // Check that prefs are set correctly.
   web_resource_service->UnpackLogoSignal(*(test_json.get()));
-  logo_start = profile.GetPrefs()->GetReal(prefs::kNTPCustomLogoStart);
-  ASSERT_EQ(logo_start, 0);  // date value reset to 0;
-  logo_end = profile.GetPrefs()->GetReal(prefs::kNTPCustomLogoEnd);
-  ASSERT_EQ(logo_end, 0);  // date value reset to 0;
+  logo_start = prefs->GetReal(prefs::kNTPCustomLogoStart);
+  EXPECT_EQ(logo_start, 0);  // date value reset to 0;
+  logo_end = prefs->GetReal(prefs::kNTPCustomLogoEnd);
+  EXPECT_EQ(logo_end, 0);  // date value reset to 0;
 }
 
 TEST_F(WebResourceServiceTest, UnpackPromoSignal) {
@@ -107,6 +122,7 @@ TEST_F(WebResourceServiceTest, UnpackPromoSignal) {
                      "    \"answers\": ["
                      "       {"
                      "        \"name\": \"promo_start\","
+                     "        \"question\": \"3:2\","
                      "        \"tooltip\": \"Eat more pie!\","
                      "        \"inproduct\": \"31/01/10 01:00 GMT\""
                      "       },"
@@ -125,13 +141,33 @@ TEST_F(WebResourceServiceTest, UnpackPromoSignal) {
 
   // Check that prefs are set correctly.
   web_resource_service->UnpackPromoSignal(*(test_json.get()));
+  PrefService* prefs = profile.GetPrefs();
+  ASSERT_TRUE(prefs != NULL);
+
+  std::string promo_line = prefs->GetString(prefs::kNTPPromoLine);
+  EXPECT_EQ(promo_line, "Eat more pie!");
+
+  int promo_group = prefs->GetInteger(prefs::kNTPPromoGroup);
+  EXPECT_GE(promo_group, 0);
+  EXPECT_LT(promo_group, 16);
+
+  int promo_build_type = prefs->GetInteger(prefs::kNTPPromoBuild);
+  EXPECT_EQ(promo_build_type & DEV_BUILD, DEV_BUILD);
+  EXPECT_EQ(promo_build_type & BETA_BUILD, BETA_BUILD);
+  EXPECT_EQ(promo_build_type & STABLE_BUILD, 0);
+
+  int promo_time_slice = prefs->GetInteger(prefs::kNTPPromoGroupTimeSlice);
+  EXPECT_EQ(promo_time_slice, 2);
+
   double promo_start =
-      profile.GetPrefs()->GetReal(prefs::kNTPPromoStart);
-  ASSERT_EQ(promo_start, 1264899600);  // unix epoch for Jan 31 2010 0100 GMT.
+      prefs->GetReal(prefs::kNTPPromoStart);
+  int64 actual_start = 1264899600 +  // unix epoch for Jan 31 2010 0100 GMT.
+      promo_group * 2 * 60 * 60;
+  EXPECT_EQ(promo_start, actual_start);
+
   double promo_end =
-      profile.GetPrefs()->GetReal(prefs::kNTPPromoEnd);
-  ASSERT_EQ(promo_end, 1327971600);  // unix epoch for Jan 31 2012 0100 GMT.
-  std::string promo_line = profile.GetPrefs()->GetString(prefs::kNTPPromoLine);
-  ASSERT_EQ(promo_line, "Eat more pie!");
+      prefs->GetReal(prefs::kNTPPromoEnd);
+  EXPECT_EQ(promo_end, 1327971600);  // unix epoch for Jan 31 2012 0100 GMT.
 }
 
+
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index d53f112..d52d503 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1022,16 +1022,27 @@ const char kNTPPrefVersion[] = "ntp.pref_version";
 const char kNTPCustomLogoStart[] = "ntp.alt_logo_start";
 const char kNTPCustomLogoEnd[] = "ntp.alt_logo_end";
 
-// Dates between which the NTP should show a promotional line downloaded
-// from the promo server.
-const char kNTPPromoStart[] = "ntp.promo_start";
-const char kNTPPromoEnd[] = "ntp.promo_end";
+// Whether promo should be shown to Dev builds, Beta and Dev, or all builds.
+const char kNTPPromoBuild[] = "ntp.promo_build";
+
+// True if user has explicitly closed the promo line.
+const char kNTPPromoClosed[] = "ntp.promo_closed";
+
+// Users are randomly divided into 16 groups in order to slowly roll out
+// special promos.
+const char kNTPPromoGroup[] = "ntp.promo_group";
+
+// Amount of time each promo group should be shown a promo that is being slowly
+// rolled out, in hours.
+const char kNTPPromoGroupTimeSlice[] = "ntp.promo_group_timeslice";
 
 // Promo line from server.
 const char kNTPPromoLine[] = "ntp.promo_line";
 
-// True if user has explicitly closed the promo line.
-const char kNTPPromoClosed[] = "ntp.promo_closed";
+// Dates between which the NTP should show a promotional line downloaded
+// from the promo server.
+const char kNTPPromoStart[] = "ntp.promo_start";
+const char kNTPPromoEnd[] = "ntp.promo_end";
 
 const char kDevToolsDisabled[] = "devtools.disabled";
 
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index e1fab64..327a49a 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -369,6 +369,9 @@ extern const char kNTPPromoStart[];
 extern const char kNTPPromoEnd[];
 extern const char kNTPPromoLine[];
 extern const char kNTPPromoClosed[];
+extern const char kNTPPromoGroup[];
+extern const char kNTPPromoGroupTimeSlice[];
+extern const char kNTPPromoBuild[];
 
 extern const char kDevToolsDisabled[];
 extern const char kDevToolsOpenDocked[];