Add a histogram for tracking web store promo

chrome/browser/extensions/default_apps.cc

 // Copyright (c) 2010 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/extensions/default_apps.h"
 
 #include "base/command_line.h"
+#include "base/metrics/histogram.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 
 const int DefaultApps::kAppsPromoCounterMax = 10;
 
 // static
 void DefaultApps::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterBooleanPref(prefs::kDefaultAppsInstalled, false);
   prefs->RegisterIntegerPref(prefs::kAppsPromoCounter, 0);
@@ skipping 59 matching lines @@
     NOTREACHED() << "Should not show promo until default apps are installed.";
     return;
   }
 
   int promo_counter = GetPromoCounter();
   if (promo_counter == kAppsPromoCounterMax) {
     NOTREACHED() << "Promo has already been shown the maximum number of times.";
     return;
   }
 
-  if (promo_counter < kAppsPromoCounterMax)
+  if (promo_counter < kAppsPromoCounterMax) {
+    if (promo_counter + 1 == kAppsPromoCounterMax)
+      UMA_HISTOGRAM_ENUMERATION(extension_misc::kAppsPromoHistogram,
+                                extension_misc::PROMO_EXPIRE,
+                                extension_misc::PROMO_BUCKET_BOUNDARY);
     SetPromoCounter(++promo_counter);
-  else
+  } else {
     SetPromoHidden();
+  }
 }
 
 void DefaultApps::SetPromoHidden() {
   SetPromoCounter(kAppsPromoCounterMax);
 }
 
 int DefaultApps::GetPromoCounter() const {
   return prefs_->GetInteger(prefs::kAppsPromoCounter);
 }
 
 void DefaultApps::SetPromoCounter(int val) {
   prefs_->SetInteger(prefs::kAppsPromoCounter, val);
   prefs_->ScheduleSavePersistentPrefs();
 }
 
 bool DefaultApps::GetDefaultAppsInstalled() const {
   return prefs_->GetBoolean(prefs::kDefaultAppsInstalled);
 }
 
 void DefaultApps::SetDefaultAppsInstalled(bool val) {
   prefs_->SetBoolean(prefs::kDefaultAppsInstalled, val);
   prefs_->ScheduleSavePersistentPrefs();
 }