remove ntp app install hint

chrome/browser/ui/webui/ntp/app_launcher_handler.cc

 // Copyright (c) 2012 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/ui/webui/ntp/app_launcher_handler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/auto_reset.h"
@@ skipping 819 matching lines @@
 
 void AppLauncherHandler::CleanupAfterUninstall() {
   extension_id_prompting_.clear();
 }
 
 // static
 void AppLauncherHandler::RecordAppLaunchType(
     extension_misc::AppLaunchBucket bucket) {
   UMA_HISTOGRAM_ENUMERATION(extension_misc::kAppLaunchHistogram, bucket,
                             extension_misc::APP_LAUNCH_BUCKET_BOUNDARY);
-
-  static const bool webstore_link_experiment_exists =
-      base::FieldTrialList::TrialExists(kWebStoreLinkExperiment);
-  if (webstore_link_experiment_exists) {
-    UMA_HISTOGRAM_ENUMERATION(
-        base::FieldTrial::MakeName(extension_misc::kAppLaunchHistogram,
-                                   kWebStoreLinkExperiment),
-        bucket,
-        extension_misc::APP_LAUNCH_BUCKET_BOUNDARY);
-  }
 }
 
 // static
 void AppLauncherHandler::RecordWebStoreLaunch(bool promo_active) {
   RecordAppLaunchType(extension_misc::APP_LAUNCH_NTP_WEBSTORE);
 
   if (!promo_active) return;
 
   UMA_HISTOGRAM_ENUMERATION(extension_misc::kAppsPromoHistogram,
                             extension_misc::PROMO_LAUNCH_WEB_STORE,
@@ skipping 132 matching lines @@
 
 void AppLauncherHandler::UninstallDefaultApps() {
   AppsPromo* apps_promo = extension_service_->apps_promo();
   const ExtensionIdSet& app_ids = apps_promo->old_default_apps();
   for (ExtensionIdSet::const_iterator iter = app_ids.begin();
        iter != app_ids.end(); ++iter) {
     if (extension_service_->GetExtensionById(*iter, true))
       extension_service_->UninstallExtension(*iter, false, NULL);
   }
 }