Provide user demographics to UMA from browser.

Summary of changes:
 * Piped demographic metrics provider with chrome browser (iOS + others).
 * Expose user demographics from DemographicMetricsProvider.

TBR=treib@chromium.org

Bug: 979371
Change-Id: Ib0d1eff9b767cf121fe768a9a46a3ff1fb57dd27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1687019
Commit-Queue: Vincent Boisselle <vincb@google.com>
Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680540}

chrome/browser/BUILD.gn

@@ -1974,6 +1974,7 @@ jumbo_split_static_library("browser") {
     "//components/leveldb_proto/content:factory",
     "//components/metrics:call_stack_profile_collector",
     "//components/metrics:component_metrics",
+    "//components/metrics:demographic_metrics_provider",
     "//components/metrics:gpu",
     "//components/metrics:net",
     "//components/metrics:ui",
@@ -3653,7 +3654,7 @@ jumbo_split_static_library("browser") {
     ]
   }
 
-  if (is_chromeos || enable_extensions) {
+  if (is_chromeos || enable_extensions || is_android) {
     sources += [
       "metrics/cached_metrics_profile.cc",
       "metrics/cached_metrics_profile.h",

chrome/browser/metrics/chrome_metrics_service_client.cc

@@ -38,6 +38,7 @@
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/google/google_brand.h"
 #include "chrome/browser/history/history_service_factory.h"
+#include "chrome/browser/metrics/cached_metrics_profile.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/browser/metrics/chrome_stability_metrics_provider.h"
 #include "chrome/browser/metrics/desktop_platform_features_metrics_provider.h"
@@ -67,6 +68,7 @@
 #include "components/metrics/call_stack_profile_metrics_provider.h"
 #include "components/metrics/component_metrics_provider.h"
 #include "components/metrics/cpu_metrics_provider.h"
+#include "components/metrics/demographic_metrics_provider.h"
 #include "components/metrics/drive_metrics_provider.h"
 #include "components/metrics/field_trials_provider.h"
 #include "components/metrics/gpu/gpu_metrics_provider.h"
@@ -85,6 +87,7 @@
 #include "components/metrics/ui/screen_info_metrics_provider.h"
 #include "components/metrics/url_constants.h"
 #include "components/metrics/version_utils.h"
+#include "components/network_time/network_time_tracker.h"
 #include "components/omnibox/browser/omnibox_metrics_provider.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
@@ -390,6 +393,45 @@ bool IsProcessRunning(base::ProcessId pid) {
   return false;
 }
 
+// Client used by DemographicMetricsProvider to retrieve Profile information.
+class ProfileClientImpl
+    : public metrics::DemographicMetricsProvider::ProfileClient {
+ public:
+  ~ProfileClientImpl() override {}
+  ProfileClientImpl() = default;
+
+  int GetNumberOfProfilesOnDisk() override {
+    return g_browser_process->profile_manager()->GetNumberOfProfiles();
+  }
+
+  syncer::SyncService* GetSyncService() override {
+    Profile* profile = cached_metrics_profile_.GetMetricsProfile();
+    if (!profile)
+      return nullptr;
+
+    return ProfileSyncServiceFactory::GetForProfile(profile);
+  }
+
+  base::Time GetNetworkTime() const override {
+    base::Time time;
+    if (g_browser_process->network_time_tracker()->GetNetworkTime(&time,
+                                                                  nullptr) !=
+        network_time::NetworkTimeTracker::NETWORK_TIME_AVAILABLE) {
+      // Return null time to indicate that it could not get the network time. It
+      // is the responsibility of the client to have the strategy to deal with
+      // the absence of network time.
+      return base::Time();
+    }
+    return time;
+  }
+
+ private:
+  // Provides the same cached Profile each time.
+  metrics::CachedMetricsProfile cached_metrics_profile_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProfileClientImpl);
+};
+
 }  // namespace
 
 // UKM suffix for field trial recording.
@@ -644,6 +686,10 @@ void ChromeMetricsServiceClient::RegisterMetricsServiceProviders() {
   metrics_service_->RegisterMetricsProvider(
       std::make_unique<tracing::BackgroundTracingMetricsProvider>());
 
+  metrics_service_->RegisterMetricsProvider(
+      std::make_unique<metrics::DemographicMetricsProvider>(
+          std::make_unique<ProfileClientImpl>()));
+
 #if defined(OS_ANDROID)
   metrics_service_->RegisterMetricsProvider(
       std::make_unique<AndroidMetricsProvider>());

chrome/browser/metrics/chrome_metrics_service_client_unittest.cc

@@ -156,7 +156,7 @@ TEST_F(ChromeMetricsServiceClientTest, TestRegisterMetricsServiceProviders) {
   size_t expected_providers = 3;
 
   // This is the number of metrics providers that are outside any #if macros.
-  expected_providers += 17;
+  expected_providers += 18;
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   expected_providers++;  // ExtensionsMetricsProvider.

components/metrics/BUILD.gn

@@ -5,6 +5,24 @@
 import("//build/config/jumbo.gni")
 import("//testing/test.gni")
 
+static_library("demographic_metrics_provider") {
+  sources = [
+    "demographic_metrics_provider.cc",
+    "demographic_metrics_provider.h",
+  ]
+
+  public_deps = [
+    "//third_party/metrics_proto",
+  ]
+
+  deps = [
+    ":metrics",
+    "//base",
+    "//components/sync/base",
+    "//components/sync/driver",
+  ]
+}
+
 jumbo_static_library("metrics") {
   sources = [
     "call_stack_profile_metrics_provider.cc",
@@ -23,8 +41,6 @@ jumbo_static_library("metrics") {
     "data_use_tracker.h",
     "delegating_provider.cc",
     "delegating_provider.h",
-    "demographic_metrics_provider.cc",
-    "demographic_metrics_provider.h",
     "drive_metrics_provider.cc",
     "drive_metrics_provider.h",
     "drive_metrics_provider_android.cc",
@@ -397,6 +413,7 @@ source_set("unit_tests") {
   deps = [
     ":call_stack_profile_builder",
     ":component_metrics",
+    ":demographic_metrics_provider",
     ":metrics",
     ":net",
     ":single_sample_metrics",
@@ -406,6 +423,8 @@ source_set("unit_tests") {
     "//components/component_updater:test_support",
     "//components/encrypted_messages:encrypted_message_proto",
     "//components/prefs:test_support",
+    "//components/sync/base",
+    "//components/sync/driver:test_support",
     "//components/variations",
     "//extensions/buildflags",
     "//mojo/public/cpp/bindings",

components/metrics/DEPS

@@ -7,6 +7,7 @@ include_rules = [
   "+components/compression",
   "+components/metrics",
   "+components/prefs",
+  "+components/sync",
   "+components/variations",
   "+components/version_info",
   "+content/public/test",

components/metrics/demographic_metrics_provider.cc

@@ -5,55 +5,50 @@
 #include "components/metrics/demographic_metrics_provider.h"
 
 #include "base/feature_list.h"
-#include "base/metrics/histogram_functions.h"
-#include "base/metrics/histogram_macros.h"
+#include "base/optional.h"
+#include "components/sync/base/sync_prefs.h"
+#include "components/sync/base/user_demographics.h"
+#include "components/sync/driver/sync_service.h"
 
 namespace metrics {
 
-namespace {
-
-// TODO(crbug/979371): Implement this.
-// Gets user's birth year from Profile prefs that are provided by |service|.
-// Returns false if could not retrieve birth year.
-bool GetUserBirthYear(const PrefService& service, int* birth_year) {
-  *birth_year = 1990;
-  return true;
-}
-
-// TODO(crbug/979371): Implement this.
-// Gets user's gender from Profile prefs that are provided by |service|. Returns
-// false if could not retrieve birth year.
-bool GetUserGender(const PrefService& service,
-                   UserDemographicsProto::Gender* gender) {
-  *gender = UserDemographicsProto::GENDER_UNKNOWN_OR_OTHER;
-  return true;
-}
-
-}  // namespace
+// static
+const base::Feature DemographicMetricsProvider::kDemographicMetricsReporting = {
+    "DemographicMetricsReporting", base::FEATURE_DISABLED_BY_DEFAULT};
 
 DemographicMetricsProvider::DemographicMetricsProvider(
-    PrefService* pref_service)
-    : pref_service_(pref_service) {
-  // TODO(crbug/979371): Remove this log. Only there to avoid compilation error.
-  DVLOG(1) << "Using pref service instance at: " << pref_service_;
+    std::unique_ptr<ProfileClient> profile_client)
+    : profile_client_(std::move(profile_client)) {
+  DCHECK(profile_client_);
 }
 
+DemographicMetricsProvider::~DemographicMetricsProvider() {}
+
 void DemographicMetricsProvider::ProvideCurrentSessionData(
     ChromeUserMetricsExtension* uma_proto) {
   // Skip if feature disabled.
   if (!base::FeatureList::IsEnabled(kDemographicMetricsReporting))
     return;
 
-  int birth_year;
-  if (GetUserBirthYear(*pref_service_, &birth_year))
-    uma_proto->mutable_user_demographics()->set_birth_year(birth_year);
-  UserDemographicsProto::Gender user_gender;
-  if (GetUserGender(*pref_service_, &user_gender))
-    uma_proto->mutable_user_demographics()->set_gender(user_gender);
-}
+  // Skip if not exactly one Profile on disk. Having more than one Profile that
+  // is using the browser can make demographics less relevant. This approach
+  // cannot determine if there is more than 1 distinct user using the Profile.
+  if (profile_client_->GetNumberOfProfilesOnDisk() != 1)
+    return;
 
-// static
-const base::Feature DemographicMetricsProvider::kDemographicMetricsReporting = {
-    "DemographicMetricsReporting", base::FEATURE_DISABLED_BY_DEFAULT};
+  syncer::SyncService* sync_service = profile_client_->GetSyncService();
+  // Skip if no sync service.
+  if (!sync_service)
+    return;
+
+  // Report demographics if they are available.
+  base::Optional<syncer::UserDemographics> demographics =
+      sync_service->GetUserDemographics(profile_client_->GetNetworkTime());
+  if (demographics.has_value()) {
+    auto* demographics_proto = uma_proto->mutable_user_demographics();
+    demographics_proto->set_birth_year(demographics->birth_year);
+    demographics_proto->set_gender(demographics->gender);
+  }
+}
 
 }  // namespace metrics

components/metrics/demographic_metrics_provider.h

@@ -5,8 +5,11 @@
 #ifndef COMPONENTS_METRICS_DEMOGRAPHIC_METRICS_PROVIDER_H_
 #define COMPONENTS_METRICS_DEMOGRAPHIC_METRICS_PROVIDER_H_
 
+#include <memory>
+
+#include "base/time/time.h"
 #include "components/metrics/metrics_provider.h"
-#include "components/prefs/pref_service.h"
+#include "components/sync/driver/sync_service.h"
 #include "third_party/metrics_proto/chrome_user_metrics_extension.pb.h"
 
 namespace base {
@@ -17,21 +20,35 @@ namespace metrics {
 
 class DemographicMetricsProvider : public MetricsProvider {
  public:
-  // Constructs a demographic metrics provider that gets demographic data from
-  // |pref_service|, which must outlive the use of an object of this class.
-  explicit DemographicMetricsProvider(PrefService* pref_service);
-  ~DemographicMetricsProvider() override = default;
+  // Interface that represents the client that retrieves Profile information.
+  class ProfileClient {
+   public:
+    virtual ~ProfileClient() = default;
+
+    // Gets the total number of profiles that are on disk (loaded + not loaded)
+    // for the browser.
+    virtual int GetNumberOfProfilesOnDisk() = 0;
+
+    // Gets a weak pointer to the ProfileSyncService of the Profile.
+    virtual syncer::SyncService* GetSyncService() = 0;
+
+    // Gets the network time that represents now.
+    virtual base::Time GetNetworkTime() const = 0;
+  };
+
+  explicit DemographicMetricsProvider(
+      std::unique_ptr<ProfileClient> profile_client);
+  ~DemographicMetricsProvider() override;
 
   // MetricsProvider:
   void ProvideCurrentSessionData(
       ChromeUserMetricsExtension* uma_proto) override;
 
-  // Feature switch for reporting demographic data.
+  // Feature switch to report user demographic data.
   static const base::Feature kDemographicMetricsReporting;
 
  private:
-  // Preference Service to get profile prefs from.
-  PrefService* const pref_service_;
+  std::unique_ptr<ProfileClient> profile_client_;
 
   DISALLOW_COPY_AND_ASSIGN(DemographicMetricsProvider);
 };

components/metrics/demographic_metrics_provider_unittest.cc

@@ -4,32 +4,109 @@
 
 #include "components/metrics/demographic_metrics_provider.h"
 
+#include <memory>
+
+#include "base/optional.h"
 #include "base/test/scoped_feature_list.h"
+#include "base/test/simple_test_clock.h"
+#include "base/time/time.h"
+#include "components/sync/base/sync_prefs.h"
+#include "components/sync/base/user_demographics.h"
+#include "components/sync/driver/test_sync_service.h"
+#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/metrics_proto/chrome_user_metrics_extension.pb.h"
 
 namespace metrics {
 namespace {
 
+// Profile client for testing that gets fake Profile information and services.
+class TestProfileClient : public DemographicMetricsProvider::ProfileClient {
+ public:
+  ~TestProfileClient() override = default;
+
+  TestProfileClient(std::unique_ptr<syncer::SyncService> sync_service,
+                    int number_of_profiles)
+      : sync_service_(std::move(sync_service)),
+        number_of_profiles_(number_of_profiles) {}
+
+  int GetNumberOfProfilesOnDisk() override { return number_of_profiles_; }
+
+  syncer::SyncService* GetSyncService() override { return sync_service_.get(); }
+
+  base::Time GetNetworkTime() const override {
+    base::Time time;
+    auto result = base::Time::FromString("17 Jun 2019 00:00:00 UDT", &time);
+    DCHECK(result);
+    return time;
+  }
+
+ private:
+  std::unique_ptr<syncer::SyncService> sync_service_;
+  const int number_of_profiles_;
+  base::SimpleTestClock clock_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestProfileClient);
+};
+
+// Make arbitrary user demographics to provide.
+base::Optional<syncer::UserDemographics> GetDemographics() {
+  base::Optional<syncer::UserDemographics> user_demographics =
+      syncer::UserDemographics();
+  user_demographics->birth_year = 1983;
+  user_demographics->gender = UserDemographicsProto::GENDER_FEMALE;
+  return user_demographics;
+}
+
+std::unique_ptr<TestProfileClient> MakeTestProfileClient(
+    const base::Optional<syncer::UserDemographics>& user_demographics,
+    int number_of_profiles,
+    bool has_sync_service) {
+  std::unique_ptr<syncer::TestSyncService> sync_service = nullptr;
+  if (has_sync_service) {
+    sync_service = std::make_unique<syncer::TestSyncService>();
+    sync_service->SetUserDemographics(user_demographics);
+  }
+  return std::make_unique<TestProfileClient>(std::move(sync_service),
+                                             number_of_profiles);
+}
+
 TEST(DemographicMetricsProviderTest, ProvideCurrentSessionData_FeatureEnabled) {
   // Enable demographics reporting feature.
   base::test::ScopedFeatureList local_feature;
   local_feature.InitAndEnableFeature(
       DemographicMetricsProvider::kDemographicMetricsReporting);
 
+  // Run demographics provider.
+  DemographicMetricsProvider provider(
+      MakeTestProfileClient(GetDemographics(), /*number_of_profiles=*/1,
+                            /*has_sync_service=*/true));
   ChromeUserMetricsExtension uma_proto;
-
-  DemographicMetricsProvider provider(/*pref_service=*/nullptr);
   provider.ProvideCurrentSessionData(&uma_proto);
 
-  // Demographics are hard-coded in the provider for now, see crbug/979371.
-  const int test_user_birthyear_bucket = 1990;
-  const UserDemographicsProto::Gender test_user_gender =
-      UserDemographicsProto::GENDER_UNKNOWN_OR_OTHER;
-
-  EXPECT_EQ(test_user_birthyear_bucket,
+  // Verify provided demographics.
+  EXPECT_EQ(GetDemographics()->birth_year,
             uma_proto.user_demographics().birth_year());
-  EXPECT_EQ(test_user_gender, uma_proto.user_demographics().gender());
+  EXPECT_EQ(GetDemographics()->gender, uma_proto.user_demographics().gender());
+}
+
+TEST(DemographicMetricsProviderTest, ProvideCurrentSessionData_NoSyncService) {
+  // Enable demographics reporting feature.
+  base::test::ScopedFeatureList local_feature;
+  local_feature.InitAndDisableFeature(
+      DemographicMetricsProvider::kDemographicMetricsReporting);
+
+  // Run demographics provider.
+  DemographicMetricsProvider provider(
+      MakeTestProfileClient(GetDemographics(),
+                            /*number_of_profiles=*/1,
+                            /*has_sync_service=*/false));
+  ChromeUserMetricsExtension uma_proto;
+  provider.ProvideCurrentSessionData(&uma_proto);
+
+  // Expect the proto fields to be not set and left to default.
+  EXPECT_FALSE(uma_proto.user_demographics().has_birth_year());
+  EXPECT_FALSE(uma_proto.user_demographics().has_gender());
 }
 
 TEST(DemographicMetricsProviderTest,
@@ -39,13 +116,53 @@ TEST(DemographicMetricsProviderTest,
   local_feature.InitAndDisableFeature(
       DemographicMetricsProvider::kDemographicMetricsReporting);
 
+  // Run demographics provider.
+  DemographicMetricsProvider provider(
+      MakeTestProfileClient(GetDemographics(), /*number_of_profiles=*/1,
+                            /*has_sync_service=*/true));
   ChromeUserMetricsExtension uma_proto;
+  provider.ProvideCurrentSessionData(&uma_proto);
 
-  DemographicMetricsProvider provider(/*pref_service=*/nullptr);
+  // Expect that the UMA proto is untouched.
+  EXPECT_FALSE(uma_proto.user_demographics().has_birth_year());
+  EXPECT_FALSE(uma_proto.user_demographics().has_gender());
+}
+
+TEST(DemographicMetricsProviderTest,
+     ProvideCurrentSessionData_NotExactlyOneProfile) {
+  // Enable demographics reporting feature.
+  base::test::ScopedFeatureList local_feature;
+  local_feature.InitAndEnableFeature(
+      DemographicMetricsProvider::kDemographicMetricsReporting);
+
+  // Run demographics provider with not exactly one Profile on disk.
+  DemographicMetricsProvider provider(
+      MakeTestProfileClient(GetDemographics(), /*number_of_profiles=*/2,
+                            /*has_sync_service=*/true));
+  ChromeUserMetricsExtension uma_proto;
+  provider.ProvideCurrentSessionData(&uma_proto);
+
+  // Expect that the UMA proto is untouched.
+  EXPECT_FALSE(uma_proto.user_demographics().has_birth_year());
+  EXPECT_FALSE(uma_proto.user_demographics().has_gender());
+}
+
+TEST(DemographicMetricsProviderTest,
+     ProvideCurrentSessionData_NoUserDemographics) {
+  // Enable demographics reporting feature.
+  base::test::ScopedFeatureList local_feature;
+  local_feature.InitAndEnableFeature(
+      DemographicMetricsProvider::kDemographicMetricsReporting);
+
+  // Run demographics provider with a ProfileClient that does not provide
+  // demographics.
+  DemographicMetricsProvider provider(
+      MakeTestProfileClient(base::nullopt, /*number_of_profiles=*/1,
+                            /*has_sync_service=*/true));
+  ChromeUserMetricsExtension uma_proto;
   provider.ProvideCurrentSessionData(&uma_proto);
 
-  // Expect that the UMA proto is untouched and has default data when feature
-  // disabled.
+  // Expect that the UMA proto is untouched.
   EXPECT_FALSE(uma_proto.user_demographics().has_birth_year());
   EXPECT_FALSE(uma_proto.user_demographics().has_gender());
 }

ios/chrome/browser/metrics/BUILD.gn

@@ -28,6 +28,22 @@ source_set("features") {
   ]
 }
 
+source_set("chrome_browser_state_client") {
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [
+    "chrome_browser_state_client.h",
+    "chrome_browser_state_client.mm",
+  ]
+  deps = [
+    "//base",
+    "//components/metrics:demographic_metrics_provider",
+    "//components/network_time",
+    "//ios/chrome/browser",
+    "//ios/chrome/browser/browser_state",
+    "//ios/chrome/browser/sync",
+  ]
+}
+
 source_set("metrics") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
@@ -57,6 +73,7 @@ source_set("metrics") {
     ":ukm_url_recorder",
   ]
   deps = [
+    ":chrome_browser_state_client",
     ":features",
     "//base",
     "//components/browser_sync",
@@ -64,6 +81,7 @@ source_set("metrics") {
     "//components/keyed_service/core",
     "//components/keyed_service/ios",
     "//components/metrics",
+    "//components/metrics:demographic_metrics_provider",
     "//components/metrics:net",
     "//components/metrics:ui",
     "//components/metrics_services_manager",
@@ -103,6 +121,7 @@ source_set("unit_tests") {
   configs += [ "//build/config/compiler:enable_arc" ]
   testonly = true
   sources = [
+    "chrome_browser_state_client_unittest.mm",
     "ios_chrome_metrics_service_accessor_unittest.cc",
     "ios_chrome_stability_metrics_provider_unittest.mm",
     "mobile_session_shutdown_metrics_provider_unittest.mm",
@@ -110,18 +129,23 @@ source_set("unit_tests") {
     "ukm_url_recorder_unittest.mm",
   ]
   deps = [
+    ":chrome_browser_state_client",
     ":metrics",
     "//base",
     "//base/test:test_support",
     "//components/metrics",
     "//components/metrics:test_support",
+    "//components/network_time:network_time",
     "//components/prefs",
     "//components/prefs:test_support",
     "//components/ukm:test_support",
     "//components/version_info",
+    "//ios/chrome/browser",
+    "//ios/chrome/browser/browser_state:test_support",
     "//ios/chrome/browser/web:test_support",
     "//ios/chrome/test:test_support",
     "//ios/web/public:public",
+    "//ios/web/public/test",
     "//ios/web/public/test/fakes",
     "//net:test_support",
     "//testing/gtest",

ios/chrome/browser/metrics/chrome_browser_state_client.h

+// Copyright 2019 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.
+
+#ifndef IOS_CHROME_BROWSER_METRICS_CHROME_BROWSER_STATE_CLIENT_H_
+#define IOS_CHROME_BROWSER_METRICS_CHROME_BROWSER_STATE_CLIENT_H_
+
+#include "base/macros.h"
+#include "components/metrics/demographic_metrics_provider.h"
+
+namespace metrics {
+
+// Client used by DemographicMetricsProvider to retrieve Profile information.
+class ChromeBrowserStateClient
+    : public metrics::DemographicMetricsProvider::ProfileClient {
+ public:
+  ~ChromeBrowserStateClient() override;
+  ChromeBrowserStateClient() = default;
+
+  // DemographicMetricsProvider::ProfileClient:
+  int GetNumberOfProfilesOnDisk() override;
+  syncer::SyncService* GetSyncService() override;
+  base::Time GetNetworkTime() const override;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeBrowserStateClient);
+};
+
+}  //    namespace metrics
+
+#endif  // IOS_CHROME_BROWSER_METRICS_CHROME_BROWSER_STATE_CLIENT_H_

ios/chrome/browser/metrics/chrome_browser_state_client.mm

+// Copyright 2019 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 "ios/chrome/browser/metrics/chrome_browser_state_client.h"
+
+#include "components/network_time/network_time_tracker.h"
+#include "ios/chrome/browser/application_context.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_manager.h"
+#include "ios/chrome/browser/sync/profile_sync_service_factory.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace metrics {
+
+ChromeBrowserStateClient::~ChromeBrowserStateClient() {}
+
+base::Time ChromeBrowserStateClient::GetNetworkTime() const {
+  base::Time time;
+  if (GetApplicationContext()->GetNetworkTimeTracker()->GetNetworkTime(
+          &time, nullptr) !=
+      network_time::NetworkTimeTracker::NETWORK_TIME_AVAILABLE) {
+    // Return null time to indicate that it could not get the network time. It
+    // is the responsibility of the client to have the strategy to deal with the
+    // absence of network time.
+    return base::Time();
+  }
+  return time;
+}
+
+syncer::SyncService* ChromeBrowserStateClient::GetSyncService() {
+  // Get SyncService from BrowserState that was the last to be used. Will create
+  // a new BrowserState if no BrowserState exists.
+  return ProfileSyncServiceFactory::GetForBrowserState(
+      GetApplicationContext()
+          ->GetChromeBrowserStateManager()
+          ->GetLastUsedBrowserState()
+          ->GetOriginalChromeBrowserState());
+}
+
+int ChromeBrowserStateClient::GetNumberOfProfilesOnDisk() {
+  // Return 1 because there should be only one Profile available.
+  return 1;
+}
+
+}  //  namespace metrics

ios/chrome/browser/metrics/chrome_browser_state_client_unittest.mm

+// Copyright 2019 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 "ios/chrome/browser/metrics/chrome_browser_state_client.h"
+
+#include "base/time/default_clock.h"
+#include "base/time/default_tick_clock.h"
+#include "base/time/time.h"
+#include "components/network_time/network_time_tracker.h"
+#include "ios/chrome/browser/application_context.h"
+#include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
+#include "ios/chrome/browser/browser_state/test_chrome_browser_state_manager.h"
+#include "ios/chrome/test/ios_chrome_scoped_testing_chrome_browser_state_manager.h"
+#include "ios/web/public/test/test_web_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace metrics {
+
+class ChromeBrowserStateClientTest : public PlatformTest {
+ public:
+  ChromeBrowserStateClientTest()
+      : scoped_browser_state_manager_(
+            std::make_unique<TestChromeBrowserStateManager>(
+                TestChromeBrowserState::Builder().Build())) {}
+  ~ChromeBrowserStateClientTest() override {}
+
+  void SetUp() override { PlatformTest::SetUp(); }
+
+ private:
+  web::TestWebThreadBundle test_web_thread_bundle_;
+  IOSChromeScopedTestingChromeBrowserStateManager scoped_browser_state_manager_;
+};
+
+TEST_F(ChromeBrowserStateClientTest, GetNetworkTime) {
+  // Set initial time of the network clock.
+  base::TimeDelta resolution = base::TimeDelta::FromMilliseconds(17);
+  base::TimeDelta latency = base::TimeDelta::FromMilliseconds(50);
+  base::DefaultClock clock;
+  base::DefaultTickClock tick_clock;
+  GetApplicationContext()->GetNetworkTimeTracker()->UpdateNetworkTime(
+      clock.Now() - latency / 2, resolution, latency, tick_clock.NowTicks());
+
+  // Verify network clock gives non-null time.
+  ChromeBrowserStateClient profile_client;
+  EXPECT_FALSE(profile_client.GetNetworkTime().is_null());
+}
+
+TEST_F(ChromeBrowserStateClientTest, GetSyncService) {
+  ChromeBrowserStateClient profile_client;
+  // Verify if it possible to retrieve the instance of the SyncService
+  // associated with the ChromeBrowserState.
+  EXPECT_TRUE(profile_client.GetSyncService());
+}
+
+TEST_F(ChromeBrowserStateClientTest, GetNumberOfProfilesOnDisk) {
+  ChromeBrowserStateClient profile_client;
+  EXPECT_EQ(1, profile_client.GetNumberOfProfilesOnDisk());
+}
+
+}  // namespace metrics

ios/chrome/browser/metrics/ios_chrome_metrics_service_client.mm

@@ -24,6 +24,7 @@
 #include "components/history/core/browser/history_service.h"
 #include "components/keyed_service/core/service_access_type.h"
 #include "components/metrics/call_stack_profile_metrics_provider.h"
+#include "components/metrics/demographic_metrics_provider.h"
 #include "components/metrics/drive_metrics_provider.h"
 #include "components/metrics/metrics_log_uploader.h"
 #include "components/metrics/metrics_pref_names.h"
@@ -52,6 +53,7 @@
 #include "ios/chrome/browser/chrome_paths.h"
 #include "ios/chrome/browser/google/google_brand.h"
 #include "ios/chrome/browser/history/history_service_factory.h"
+#include "ios/chrome/browser/metrics/chrome_browser_state_client.h"
 #include "ios/chrome/browser/metrics/ios_chrome_stability_metrics_provider.h"
 #include "ios/chrome/browser/metrics/ios_user_type_metrics_provider.h"
 #include "ios/chrome/browser/metrics/mobile_session_shutdown_metrics_provider.h"
@@ -242,6 +244,10 @@ void IOSChromeMetricsServiceClient::Initialize() {
 
   metrics_service_->RegisterMetricsProvider(
       std::make_unique<IOSUserTypeMetricsProvider>());
+
+  metrics_service_->RegisterMetricsProvider(
+      std::make_unique<metrics::DemographicMetricsProvider>(
+          std::make_unique<metrics::ChromeBrowserStateClient>()));
 }
 
 void IOSChromeMetricsServiceClient::CollectFinalHistograms() {