Add a new App launcher promo to the apps page / NTP.

apps/field_trial_names.cc

+// Copyright 2013 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 "apps/field_trial_names.h"
+
+namespace apps {
+
+// The field trial group name that enables showing the promo.
+const char kShowLauncherPromoOnceGroupName[] = "ShowPromoUntilDismissed";
+
+// The field trial group name that resets the pref to show the app launcher
+// promo on every session startup.
+const char kResetShowLauncherPromoPrefGroupName[] = "ResetShowPromoPref";
+
+// The name of the field trial that controls showing the app launcher promo.
+const char kLauncherPromoTrialName[] = "ShowAppLauncherPromo";
+
+}  // namespace apps