Clean up sparse_histogram.h header

chrome/browser/notifications/google_now_notification_stats_collector.cc

 // Copyright 2014 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/notifications/google_now_notification_stats_collector.h"
 
 #include <string>
 
-#include "base/metrics/sparse_histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/notifications/extension_welcome_notification.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "content/public/browser/user_metrics.h"
 #include "ui/message_center/notification.h"
 
 namespace {
 const int kNotificationsMaxCount = 20;
 }
@@ skipping 53 matching lines @@
   int google_now_notification_count = 0;
   for (Notifications::iterator iter = visible_notifications.begin();
       iter != visible_notifications.end();
       ++iter) {
     if ((*iter)->notifier_id().id ==
             ExtensionWelcomeNotification::kChromeNowExtensionID)
       google_now_notification_count++;
   }
   return google_now_notification_count;
 }