ntp: track number of times a user switches pages in a single session

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

 // 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/ui/webui/ntp/new_tab_page_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/field_trial.h"
@@ skipping 10 matching lines @@
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
 static const int kIntroDisplayMax = 10;
 
 // The URL of a knowledge-base article about the new NTP.
 static const char kNTP4IntroURL[] =
   "http://www.google.com/support/chrome/bin/answer.py?answer=95451";
 
+NewTabPageHandler::NewTabPageHandler() : page_switch_count_(0) {
+}
+
+NewTabPageHandler::~NewTabPageHandler() {
+  HISTOGRAM_COUNTS_100("NewTabPage.SingleSessionPageSwitches",
+                       page_switch_count_);
+}
+
 WebUIMessageHandler* NewTabPageHandler::Attach(WebUI* web_ui) {
   // Record an open of the NTP with its default page type.
   PrefService* prefs = Profile::FromWebUI(web_ui)->GetPrefs();
   int shown_page_type = prefs->GetInteger(prefs::kNTPShownPage) >>
       kPageIdOffset;
   UMA_HISTOGRAM_ENUMERATION("NewTabPage.DefaultPageType",
                             shown_page_type, kHistogramEnumerationMax);
 
   static bool default_apps_trial_exists =
       base::FieldTrialList::TrialExists(kDefaultAppsTrialName);
@@ skipping 33 matching lines @@
 }
 
 void NewTabPageHandler::HandleNotificationPromoViewed(const ListValue* args) {
   scoped_refptr<NotificationPromo> notification_promo =
       NotificationPromo::Create(Profile::FromWebUI(web_ui_), NULL);
   if (notification_promo->HandleViewed())
     Notify(chrome::NOTIFICATION_PROMO_RESOURCE_STATE_CHANGED);
 }
 
 void NewTabPageHandler::HandlePageSelected(const ListValue* args) {
+  page_switch_count_++;
+
   double page_id_double;
   CHECK(args->GetDouble(0, &page_id_double));
   int page_id = static_cast<int>(page_id_double);
 
   double index_double;
   CHECK(args->GetDouble(1, &index_double));
   int index = static_cast<int>(index_double);
 
   PrefService* prefs = Profile::FromWebUI(web_ui())->GetPrefs();
   int previous_shown_page =
@@ skipping 81 matching lines @@
   // is only called during startup before the ntp resource cache is constructed.
 }
 
 void NewTabPageHandler::Notify(chrome::NotificationType notification_type) {
   content::NotificationService* service =
       content::NotificationService::current();
   service->Notify(notification_type,
                   content::Source<NewTabPageHandler>(this),
                   content::NotificationService::NoDetails());
 }