Add metric for NTP default page

browser/misc_metrics/BUILD.gn

@@ -94,6 +94,7 @@ source_set("unit_tests") {
   if (!is_android) {
     sources += [
       "extension_metrics_unittest.cc",
+      "profile_new_tab_metrics_unittest.cc",
       "theme_metrics_unittest.cc",
     ]
 

browser/misc_metrics/profile_misc_metrics_service.cc

@@ -7,6 +7,7 @@
 
 #include "base/metrics/histogram_macros.h"
 #include "brave/browser/brave_stats/first_run_util.h"
+#include "brave/browser/misc_metrics/profile_new_tab_metrics.h"
 #include "brave/browser/misc_metrics/theme_metrics.h"
 #include "brave/components/misc_metrics/autofill_metrics.h"
 #include "brave/components/misc_metrics/language_metrics.h"
@@ -74,6 +75,7 @@ ProfileMiscMetricsService::ProfileMiscMetricsService(
     theme_metrics_ = std::make_unique<ThemeMetrics>(theme_service);
   }
   if (profile_prefs_) {
+    new_tab_metrics_ = std::make_unique<ProfileNewTabMetrics>(profile_prefs_);
     pref_change_registrar_.Add(
         prefs::kSearchSuggestEnabled,
         base::BindRepeating(&ProfileMiscMetricsService::ReportSimpleMetrics,

browser/misc_metrics/profile_misc_metrics_service.h

@@ -24,6 +24,7 @@ namespace misc_metrics {
 class MiscAndroidMetrics;
 #else
 class ExtensionMetrics;
+class ProfileNewTabMetrics;
 class ThemeMetrics;
 #endif
 class AutofillMetrics;
@@ -63,6 +64,7 @@ class ProfileMiscMetricsService : public KeyedService {
 #else
   std::unique_ptr<ExtensionMetrics> extension_metrics_ = nullptr;
   std::unique_ptr<ThemeMetrics> theme_metrics_ = nullptr;
+  std::unique_ptr<ProfileNewTabMetrics> new_tab_metrics_ = nullptr;
 #endif
 };
 

browser/misc_metrics/profile_new_tab_metrics.cc

@@ -0,0 +1,69 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/browser/misc_metrics/profile_new_tab_metrics.h"
+
+#include <optional>
+
+#include "base/containers/contains.h"
+#include "base/metrics/histogram_macros.h"
+#include "brave/browser/new_tab/new_tab_shows_options.h"
+#include "brave/components/constants/pref_names.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_service.h"
+#include "url/gurl.h"
+
+namespace misc_metrics {
+
+ProfileNewTabMetrics::ProfileNewTabMetrics(PrefService* profile_prefs)
+    : profile_prefs_(profile_prefs) {
+  pref_change_registrar_.Init(profile_prefs_);
+
+  auto callback = base::BindRepeating(
+      &ProfileNewTabMetrics::ReportNewTabPageDefault, base::Unretained(this));
+  pref_change_registrar_.Add(kNewTabPageShowsOptions, callback);
+  pref_change_registrar_.Add(prefs::kHomePage, callback);
+  pref_change_registrar_.Add(prefs::kHomePageIsNewTabPage, callback);
+
+  // Report the initial state
+  ReportNewTabPageDefault();
+}
+
+ProfileNewTabMetrics::~ProfileNewTabMetrics() = default;
+
+void ProfileNewTabMetrics::ReportNewTabPageDefault() {
+  std::optional<NewTabPageDefaultType> type;
+  brave::NewTabPageShowsOptions option =
+      static_cast<brave::NewTabPageShowsOptions>(
+          profile_prefs_->GetInteger(kNewTabPageShowsOptions));
+
+  if (option == brave::NewTabPageShowsOptions::kDashboard) {
+    type = NewTabPageDefaultType::kDashboard;
+  } else if (option == brave::NewTabPageShowsOptions::kHomepage) {
+    if (profile_prefs_->GetBoolean(prefs::kHomePageIsNewTabPage)) {
+      type = NewTabPageDefaultType::kDashboard;
+    } else {
+      GURL homepage_url(profile_prefs_->GetString(prefs::kHomePage));
+
+      if (homepage_url.host() == "search.brave.com") {
+        type = NewTabPageDefaultType::kHomepageBraveSearch;
+      } else if (base::Contains(homepage_url.host(), "google")) {
+        type = NewTabPageDefaultType::kHomepageGoogle;
+      } else if (base::Contains(homepage_url.host(), "duckduckgo")) {
+        type = NewTabPageDefaultType::kHomepageDuckDuckGo;
+      } else {
+        type = NewTabPageDefaultType::kHomepageOther;
+      }
+    }
+  } else if (option == brave::NewTabPageShowsOptions::kBlankpage) {
+    type = NewTabPageDefaultType::kBlank;
+  }
+
+  if (type) {
+    UMA_HISTOGRAM_ENUMERATION(kNewTabPageDefaultHistogramName, *type);
+  }
+}
+
+}  // namespace misc_metrics

browser/misc_metrics/profile_new_tab_metrics.h

@@ -0,0 +1,45 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_BROWSER_MISC_METRICS_PROFILE_NEW_TAB_METRICS_H_
+#define BRAVE_BROWSER_MISC_METRICS_PROFILE_NEW_TAB_METRICS_H_
+
+#include "components/prefs/pref_change_registrar.h"
+
+class PrefService;
+
+namespace misc_metrics {
+
+inline constexpr char kNewTabPageDefaultHistogramName[] =
+    "Brave.NTP.DefaultPage";
+
+enum class NewTabPageDefaultType {
+  kDashboard = 0,
+  kBlank = 1,
+  kHomepageBraveSearch = 2,
+  kHomepageGoogle = 3,
+  kHomepageDuckDuckGo = 4,
+  kHomepageOther = 5,
+  kMaxValue = kHomepageOther
+};
+
+class ProfileNewTabMetrics {
+ public:
+  explicit ProfileNewTabMetrics(PrefService* profile_prefs);
+  ~ProfileNewTabMetrics();
+
+  ProfileNewTabMetrics(const ProfileNewTabMetrics&) = delete;
+  ProfileNewTabMetrics& operator=(const ProfileNewTabMetrics&) = delete;
+
+ private:
+  void ReportNewTabPageDefault();
+
+  raw_ptr<PrefService> profile_prefs_;
+  PrefChangeRegistrar pref_change_registrar_;
+};
+
+}  // namespace misc_metrics
+
+#endif  // BRAVE_BROWSER_MISC_METRICS_PROFILE_NEW_TAB_METRICS_H_

browser/misc_metrics/profile_new_tab_metrics_unittest.cc

@@ -0,0 +1,92 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/browser/misc_metrics/profile_new_tab_metrics.h"
+
+#include "base/test/metrics/histogram_tester.h"
+#include "brave/browser/new_tab/new_tab_shows_options.h"
+#include "brave/components/constants/pref_names.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/testing_pref_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace misc_metrics {
+
+class ProfileNewTabMetricsTest : public testing::Test {
+ public:
+  ProfileNewTabMetricsTest() = default;
+
+  void SetUp() override {
+    pref_service_.registry()->RegisterIntegerPref(
+        kNewTabPageShowsOptions,
+        static_cast<int>(brave::NewTabPageShowsOptions::kDashboard));
+    pref_service_.registry()->RegisterStringPref(prefs::kHomePage, "");
+    pref_service_.registry()->RegisterBooleanPref(prefs::kHomePageIsNewTabPage,
+                                                  false);
+  }
+
+ protected:
+  TestingPrefServiceSimple pref_service_;
+  base::HistogramTester histogram_tester_;
+};
+
+TEST_F(ProfileNewTabMetricsTest, TestDashboardOption) {
+  pref_service_.SetInteger(
+      kNewTabPageShowsOptions,
+      static_cast<int>(brave::NewTabPageShowsOptions::kDashboard));
+
+  ProfileNewTabMetrics metrics(&pref_service_);
+
+  histogram_tester_.ExpectUniqueSample(kNewTabPageDefaultHistogramName, 0, 1);
+}
+
+TEST_F(ProfileNewTabMetricsTest, TestBlankOption) {
+  pref_service_.SetInteger(
+      kNewTabPageShowsOptions,
+      static_cast<int>(brave::NewTabPageShowsOptions::kBlankpage));
+
+  ProfileNewTabMetrics metrics(&pref_service_);
+
+  histogram_tester_.ExpectUniqueSample(kNewTabPageDefaultHistogramName, 1, 1);
+}
+
+TEST_F(ProfileNewTabMetricsTest, TestHomepageOptions) {
+  pref_service_.SetInteger(
+      kNewTabPageShowsOptions,
+      static_cast<int>(brave::NewTabPageShowsOptions::kHomepage));
+
+  pref_service_.SetBoolean(prefs::kHomePageIsNewTabPage, true);
+
+  ProfileNewTabMetrics metrics(&pref_service_);
+
+  histogram_tester_.ExpectUniqueSample(kNewTabPageDefaultHistogramName, 0, 1);
+
+  histogram_tester_.ExpectTotalCount(kNewTabPageDefaultHistogramName, 1);
+
+  pref_service_.SetBoolean(prefs::kHomePageIsNewTabPage, false);
+
+  histogram_tester_.ExpectBucketCount(kNewTabPageDefaultHistogramName, 5, 1);
+
+  pref_service_.SetString(prefs::kHomePage, "https://search.brave.com");
+
+  histogram_tester_.ExpectBucketCount(kNewTabPageDefaultHistogramName, 2, 1);
+
+  pref_service_.SetString(prefs::kHomePage, "https://www.google.com");
+
+  histogram_tester_.ExpectBucketCount(kNewTabPageDefaultHistogramName, 3, 1);
+
+  pref_service_.SetString(prefs::kHomePage, "https://duckduckgo.com");
+
+  histogram_tester_.ExpectBucketCount(kNewTabPageDefaultHistogramName, 4, 1);
+
+  pref_service_.SetString(prefs::kHomePage, "https://example.com");
+
+  histogram_tester_.ExpectBucketCount(kNewTabPageDefaultHistogramName, 5, 2);
+
+  histogram_tester_.ExpectTotalCount(kNewTabPageDefaultHistogramName, 6);
+}
+
+}  // namespace misc_metrics

browser/misc_metrics/sources.gni

@@ -22,6 +22,13 @@ brave_browser_misc_metrics_deps = [
   "//content/public/browser",
 ]
 
+if (!is_android) {
+  brave_browser_misc_metrics_sources += [
+    "//brave/browser/misc_metrics/profile_new_tab_metrics.cc",
+    "//brave/browser/misc_metrics/profile_new_tab_metrics.h",
+  ]
+}
+
 brave_browser_misc_metrics_android_sources = [
   "//brave/browser/misc_metrics/misc_android_metrics.cc",
   "//brave/browser/misc_metrics/misc_android_metrics_factory_android.cc",

components/p3a/metric_names.h

@@ -72,6 +72,7 @@ inline constexpr auto kCollectedTypicalHistograms =
 
     {"Brave.Importer.ImporterSource.2", {}},
     {"Brave.NTP.CustomizeUsageStatus.2", {}},
+    {"Brave.NTP.DefaultPage", {}},
     {"Brave.NTP.NewTabsCreated.3", {}},
     {"Brave.NTP.SponsoredMediaType", {}},
     {"Brave.Omnibox.SearchCount.3", {}},