Revert "Add full system profiles in .pma file as part of metrics init."

This reverts commit 87dac882.

Reason for revert: Breaks UMA recording.

Original change's description:
> Add full system profiles in .pma file as part of metrics init.
> 
> Prior to this change, only an incomplete system profile, notably
> missing field trials and uma_default_state fields, was stored
> at this point. So unclean shut downs after this point in time,
> but before the initial metrics log was saved would not include
> that info. This change fixes that by running the code that
> populates all the system profile fields.
> 
> Since we're now calling ProvideSystemProfileMetrics() twice, the
> logic in FieldTrialsProvider was no longer correct in tracking
> the log creation time. Instead, this CL updates the API to have
> that be passed in.
> 
> Additionally, Chrome OS an Screen Info providers needed updates since
> their dependencies are not yet available this early, so they are not
> able to provide all the information this early.
> 
> Finally, webview unit tests needed updating to init mojo as they are
> now exercising the provider code which has a Mojo dependency.
> 
> Bug: 992538
> TBR: sky@chromium.org
> Change-Id: Iae54398065470e390b70507d5b3ac09d5a983c9f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1746909
> Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
> Reviewed-by: Richard Coles <torne@chromium.org>
> Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
> Reviewed-by: Brian White <bcwhite@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#687000}

TBR=sky@chromium.org,rkaplow@chromium.org,asvitkine@chromium.org,torne@chromium.org,bcwhite@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 992538
Change-Id: I4a25324788960d2e61325c2a41812c5da18087f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1760869Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688146}

android_webview/lib/DEPS

@@ -9,7 +9,6 @@ include_rules = [
   "+gin/public",
   "+gin/v8_initializer.h",
   "+media/base/media_switches.h",  # For media command line switches.
-  "+mojo/core/embedder/embedder.h",
   "+ui/events/gesture_detection",
   "+ui/gl",
 ]

android_webview/lib/webview_tests.cc

@@ -6,7 +6,6 @@
 #include "base/command_line.h"
 #include "base/test/test_suite.h"
 #include "content/public/common/content_switches.h"
-#include "mojo/core/embedder/embedder.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/test/gl_surface_test_support.h"
 
@@ -15,7 +14,5 @@ int main(int argc, char** argv) {
       switches::kSingleProcess);
   gl::GLSurfaceTestSupport::InitializeNoExtensionsOneOff();
   android_webview::GpuServiceWebView::GetInstance();
-  base::TestSuite test_suite(argc, argv);
-  mojo::core::Init();
-  return test_suite.Run();
+  return base::TestSuite(argc, argv).Run();
 }

android_webview/test/BUILD.gn

@@ -353,7 +353,6 @@ test("android_webview_unittests") {
     "//components/prefs:test_support",
     "//content:content",
     "//content/test:test_support",
-    "//mojo/core/embedder",
     "//net:net",
     "//net:test_support",
     "//ui/base:ui_base_jni_headers",

chrome/browser/metrics/chromeos_metrics_provider.cc

@@ -309,11 +309,6 @@ void ChromeOSMetricsProvider::ProvideCurrentSessionData(
 
 void ChromeOSMetricsProvider::WriteBluetoothProto(
     metrics::SystemProfileProto* system_profile_proto) {
-  // This may be called before the async init task to set |adapter_| is set,
-  // such as when the persistent system profile gets filled in initially.
-  if (!adapter_)
-    return;
-
   metrics::SystemProfileProto::Hardware* hardware =
       system_profile_proto->mutable_hardware();
 

chrome/browser/startup_data.cc

@@ -78,8 +78,7 @@ void StartupData::RecordCoreSystemProfile() {
   // |field_trial_provider|.
   variations::FieldTrialsProvider field_trial_provider(nullptr,
                                                        base::StringPiece());
-  field_trial_provider.ProvideSystemProfileMetricsWithLogCreationTime(
-      base::TimeTicks(), &system_profile);
+  field_trial_provider.ProvideSystemProfileMetrics(&system_profile);
 
   // TODO(crbug.com/965482): Records information from other providers.
   metrics::GlobalPersistentSystemProfile::GetInstance()->SetSystemProfile(

components/metrics/delegating_provider.cc

@@ -63,17 +63,8 @@ bool DelegatingProvider::HasIndependentMetrics() {
 
 void DelegatingProvider::ProvideSystemProfileMetrics(
     SystemProfileProto* system_profile_proto) {
-  // ProvideSystemProfileMetricsWithLogCreationTime() should be called instead.
-  NOTREACHED();
-}
-
-void DelegatingProvider::ProvideSystemProfileMetricsWithLogCreationTime(
-    base::TimeTicks log_creation_time,
-    SystemProfileProto* system_profile_proto) {
-  for (auto& provider : metrics_providers_) {
-    provider->ProvideSystemProfileMetricsWithLogCreationTime(
-        log_creation_time, system_profile_proto);
-  }
+  for (auto& provider : metrics_providers_)
+    provider->ProvideSystemProfileMetrics(system_profile_proto);
 }
 
 bool DelegatingProvider::HasPreviousSessionData() {

components/metrics/delegating_provider.h

@@ -36,9 +36,6 @@ class DelegatingProvider final : public MetricsProvider {
   bool HasIndependentMetrics() override;
   void ProvideSystemProfileMetrics(
       SystemProfileProto* system_profile_proto) override;
-  void ProvideSystemProfileMetricsWithLogCreationTime(
-      base::TimeTicks log_creation_time,
-      SystemProfileProto* system_profile_proto) override;
   bool HasPreviousSessionData() override;
   void ProvidePreviousSessionData(
       ChromeUserMetricsExtension* uma_proto) override;

components/metrics/field_trials_provider.cc

@@ -36,14 +36,13 @@ void FieldTrialsProvider::GetFieldTrialIds(
   variations::GetFieldTrialActiveGroupIds(suffix_, field_trial_ids);
 }
 
-void FieldTrialsProvider::ProvideSystemProfileMetrics(
-    metrics::SystemProfileProto* system_profile_proto) {
-  // ProvideSystemProfileMetricsWithLogCreationTime() should be called instead.
-  NOTREACHED();
+void FieldTrialsProvider::OnDidCreateMetricsLog() {
+  if (registry_) {
+    creation_times_.push_back(base::TimeTicks::Now());
+  }
 }
 
-void FieldTrialsProvider::ProvideSystemProfileMetricsWithLogCreationTime(
-    base::TimeTicks log_creation_time,
+void FieldTrialsProvider::ProvideSystemProfileMetrics(
     metrics::SystemProfileProto* system_profile_proto) {
   std::vector<ActiveGroupId> field_trial_ids;
   const std::string& version = variations::GetSeedVersion();
@@ -53,8 +52,14 @@ void FieldTrialsProvider::ProvideSystemProfileMetricsWithLogCreationTime(
   WriteFieldTrials(field_trial_ids, system_profile_proto);
 
   if (registry_) {
+    base::TimeTicks creation_time;
+    // Should always be true, but don't crash even if there is a bug.
+    if (!creation_times_.empty()) {
+      creation_time = creation_times_.back();
+      creation_times_.pop_back();
+    }
     std::vector<ActiveGroupId> synthetic_trials;
-    registry_->GetSyntheticFieldTrialsOlderThan(log_creation_time,
+    registry_->GetSyntheticFieldTrialsOlderThan(creation_time,
                                                 &synthetic_trials);
     WriteFieldTrials(synthetic_trials, system_profile_proto);
   }

components/metrics/field_trials_provider.h

@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_METRICS_FIELD_TRIALS_PROVIDER_H_
 #define COMPONENTS_METRICS_FIELD_TRIALS_PROVIDER_H_
 
+#include <vector>
+
 #include "base/strings/string_piece.h"
 #include "base/time/time.h"
 #include "components/metrics/metrics_provider.h"
@@ -25,11 +27,9 @@ class FieldTrialsProvider : public metrics::MetricsProvider {
   ~FieldTrialsProvider() override;
 
   // metrics::MetricsProvider:
+  void OnDidCreateMetricsLog() override;
   void ProvideSystemProfileMetrics(
       metrics::SystemProfileProto* system_profile_proto) override;
-  void ProvideSystemProfileMetricsWithLogCreationTime(
-      base::TimeTicks log_creation_time,
-      metrics::SystemProfileProto* system_profile_proto) override;
 
  private:
   // Overrideable for testing.
@@ -41,7 +41,13 @@ class FieldTrialsProvider : public metrics::MetricsProvider {
   // Suffix used for the field trial names before they are hashed for uploads.
   std::string suffix_;
 
-  DISALLOW_COPY_AND_ASSIGN(FieldTrialsProvider);
+  // A stack of log creation times.
+  // While the initial metrics log exists, there will be two logs open.
+  // Use a stack so that we use the right creation time for the first ongoing
+  // log.
+  // TODO(crbug/746098): Simplify InitialMetricsLog logic so this is not
+  // necessary.
+  std::vector<base::TimeTicks> creation_times_;
 };
 
 }  // namespace variations

components/metrics/field_trials_provider_unittest.cc

@@ -96,17 +96,14 @@ TEST_F(FieldTrialsProviderTest, ProvideSyntheticTrials) {
   // Make sure these trials are older than the log.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
-  // Get the current time and wait for it to change.
-  base::TimeTicks log_creation_time = base::TimeTicks::Now();
-
+  provider.OnDidCreateMetricsLog();
   // Make sure that the log is older than the trials that should be excluded.
-  WaitUntilTimeChanges(log_creation_time);
+  WaitUntilTimeChanges(base::TimeTicks::Now());
 
   RegisterExtraSyntheticTrial();
 
   metrics::SystemProfileProto proto;
-  provider.ProvideSystemProfileMetricsWithLogCreationTime(log_creation_time,
-                                                          &proto);
+  provider.ProvideSystemProfileMetrics(&proto);
 
   ASSERT_EQ(base::size(kFieldTrialIds) + base::size(kSyntheticTrials),
             static_cast<size_t>(proto.field_trial_size()));
@@ -118,8 +115,7 @@ TEST_F(FieldTrialsProviderTest, NoSyntheticTrials) {
   TestProvider provider(nullptr, base::StringPiece());
 
   metrics::SystemProfileProto proto;
-  provider.ProvideSystemProfileMetricsWithLogCreationTime(base::TimeTicks(),
-                                                          &proto);
+  provider.ProvideSystemProfileMetrics(&proto);
 
   ASSERT_EQ(base::size(kFieldTrialIds),
             static_cast<size_t>(proto.field_trial_size()));

components/metrics/metrics_log.cc

@@ -297,10 +297,7 @@ void MetricsLog::WriteRealtimeStabilityAttributes(
 
 const SystemProfileProto& MetricsLog::RecordEnvironment(
     DelegatingProvider* delegating_provider) {
-  // Clear any previous system profile. This will be present in the case when
-  // the initial system profile got recorded on start up. Clearing it ensures
-  // there is no duplication of repeated fields.
-  uma_proto()->clear_system_profile();
+  DCHECK(!has_environment_);
   has_environment_ = true;
 
   SystemProfileProto* system_profile = uma_proto()->mutable_system_profile();
@@ -312,8 +309,7 @@ const SystemProfileProto& MetricsLog::RecordEnvironment(
   if (client_->GetBrand(&brand_code))
     system_profile->set_brand_code(brand_code);
 
-  delegating_provider->ProvideSystemProfileMetricsWithLogCreationTime(
-      creation_time_, system_profile);
+  delegating_provider->ProvideSystemProfileMetrics(system_profile);
 
   return *system_profile;
 }

components/metrics/metrics_provider.cc

@@ -48,12 +48,7 @@ void MetricsProvider::ProvideIndependentMetrics(
 }
 
 void MetricsProvider::ProvideSystemProfileMetrics(
-    SystemProfileProto* system_profile_proto) {}
-
-void MetricsProvider::ProvideSystemProfileMetricsWithLogCreationTime(
-    base::TimeTicks log_creation_time,
     SystemProfileProto* system_profile_proto) {
-  ProvideSystemProfileMetrics(system_profile_proto);
 }
 
 bool MetricsProvider::HasPreviousSessionData() {

components/metrics/metrics_provider.h

@@ -7,7 +7,6 @@
 
 #include "base/callback.h"
 #include "base/macros.h"
-#include "base/time/time.h"
 
 namespace base {
 class HistogramSnapshotManager;
@@ -65,19 +64,10 @@ class MetricsProvider {
       ChromeUserMetricsExtension* uma_proto,
       base::HistogramSnapshotManager* snapshot_manager);
 
-  // Provides additional metrics into the system profile. This is a convenience
-  // method over ProvideSystemProfileMetricsWithLogCreationTime() without the
-  // |log_creation_time| param. Should not be called directly by services.
+  // Provides additional metrics into the system profile.
   virtual void ProvideSystemProfileMetrics(
       SystemProfileProto* system_profile_proto);
 
-  // Provides additional metrics into the system profile. The log creation
-  // time param provides a timestamp of when the log was opened, which is needed
-  // for some metrics providers.
-  virtual void ProvideSystemProfileMetricsWithLogCreationTime(
-      base::TimeTicks log_creation_time,
-      SystemProfileProto* system_profile_proto);
-
   // Called once at startup to see whether this provider has critical data
   // to provide about the previous session.
   // Returning true will trigger ProvidePreviousSessionData on all other

components/metrics/metrics_service.cc

@@ -316,17 +316,16 @@ void MetricsService::EnableRecording() {
   state_manager_->ForceClientIdCreation();
   client_->SetMetricsClientId(state_manager_->client_id());
 
+  SystemProfileProto system_profile;
+  MetricsLog::RecordCoreSystemProfile(client_, &system_profile);
+  GlobalPersistentSystemProfile::GetInstance()->SetSystemProfile(
+      system_profile, /*complete=*/false);
+
   if (!log_manager_.current_log())
     OpenNewLog();
 
   delegating_provider_.OnRecordingEnabled();
 
-  // Fill in the system profile in the log and persist it (to prefs, .pma and
-  // crashpad). This includes running the providers so that information like
-  // field trials and hardware info is provided. If Chrome crashes before this
-  // log is completed, the .pma file will have this system profile.
-  RecordCurrentEnvironment(log_manager_.current_log(), /*complete=*/false);
-
   base::RemoveActionCallback(action_callback_);
   action_callback_ = base::Bind(&MetricsService::OnUserAction,
                                 base::Unretained(this));
@@ -621,7 +620,7 @@ void MetricsService::CloseCurrentLog() {
   // MetricsLog class.
   MetricsLog* current_log = log_manager_.current_log();
   DCHECK(current_log);
-  RecordCurrentEnvironment(current_log, /*complete=*/true);
+  RecordCurrentEnvironment(current_log);
   base::TimeDelta incremental_uptime;
   base::TimeDelta uptime;
   GetUptimes(local_state_, &incremental_uptime, &uptime);
@@ -753,7 +752,7 @@ bool MetricsService::PrepareInitialStabilityLog(
 void MetricsService::PrepareInitialMetricsLog() {
   DCHECK_EQ(INIT_TASK_DONE, state_);
 
-  RecordCurrentEnvironment(initial_metrics_log_.get(), /*complete=*/true);
+  RecordCurrentEnvironment(initial_metrics_log_.get());
   base::TimeDelta incremental_uptime;
   base::TimeDelta uptime;
   GetUptimes(local_state_, &incremental_uptime, &uptime);
@@ -807,14 +806,6 @@ std::unique_ptr<MetricsLog> MetricsService::CreateLog(
                                       log_type, client_);
 }
 
-void MetricsService::SetPersistentSystemProfile(
-    const std::string& serialized_proto,
-    bool complete) {
-  GlobalPersistentSystemProfile::GetInstance()->SetSystemProfile(
-      serialized_proto, complete);
-}
-
-// static
 std::string MetricsService::RecordCurrentEnvironmentHelper(
     MetricsLog* log,
     PrefService* local_state,
@@ -825,12 +816,12 @@ std::string MetricsService::RecordCurrentEnvironmentHelper(
   return recorder.SerializeAndRecordEnvironmentToPrefs(system_profile);
 }
 
-void MetricsService::RecordCurrentEnvironment(MetricsLog* log, bool complete) {
+void MetricsService::RecordCurrentEnvironment(MetricsLog* log) {
   DCHECK(client_);
   std::string serialized_proto =
       RecordCurrentEnvironmentHelper(log, local_state_, &delegating_provider_);
-
-  SetPersistentSystemProfile(serialized_proto, complete);
+  GlobalPersistentSystemProfile::GetInstance()->SetSystemProfile(
+      serialized_proto, /*complete=*/true);
   client_->OnEnvironmentUpdate(&serialized_proto);
 }
 

components/metrics/metrics_service.h

@@ -180,10 +180,6 @@ class MetricsService : public base::HistogramFlattener {
     return reporting_service_.metrics_log_store();
   }
 
-  // Sets the persistent system profile. Virtual for tests.
-  virtual void SetPersistentSystemProfile(const std::string& serialized_proto,
-                                          bool complete);
-
   // Records the current environment (system profile) in |log|, and persists
   // the results in prefs.
   // Exposed for testing.
@@ -295,7 +291,8 @@ class MetricsService : public base::HistogramFlattener {
 
   // Records the current environment (system profile) in |log|, and persists
   // the results in prefs and GlobalPersistentSystemProfile.
-  void RecordCurrentEnvironment(MetricsLog* log, bool complete);
+  // Exposed for testing.
+  void RecordCurrentEnvironment(MetricsLog* log);
 
   // Record complete list of histograms into the current log.
   // Called when we close a log.

components/metrics/metrics_service_unittest.cc

@@ -62,24 +62,7 @@ class TestMetricsService : public MetricsService {
   using MetricsService::log_store;
   using MetricsService::RecordCurrentEnvironmentHelper;
 
-  // MetricsService:
-  void SetPersistentSystemProfile(const std::string& serialized_proto,
-                                  bool complete) override {
-    persistent_system_profile_provided_ = true;
-    persistent_system_profile_complete_ = complete;
-  }
-
-  bool persistent_system_profile_provided() const {
-    return persistent_system_profile_provided_;
-  }
-  bool persistent_system_profile_complete() const {
-    return persistent_system_profile_complete_;
-  }
-
  private:
-  bool persistent_system_profile_provided_ = false;
-  bool persistent_system_profile_complete_ = false;
-
   DISALLOW_COPY_AND_ASSIGN(TestMetricsService);
 };
 
@@ -362,30 +345,6 @@ TEST_F(MetricsServiceTest, MetricsProvidersInitialized) {
   EXPECT_TRUE(test_provider->init_called());
 }
 
-TEST_F(MetricsServiceTest, SystemProfileDataProvidedOnEnableRecording) {
-  EnableMetricsReporting();
-  TestMetricsServiceClient client;
-  TestMetricsService service(GetMetricsStateManager(), &client,
-                             GetLocalState());
-
-  TestMetricsProvider* test_provider = new TestMetricsProvider();
-  service.RegisterMetricsProvider(
-      std::unique_ptr<MetricsProvider>(test_provider));
-
-  service.InitializeMetricsRecordingState();
-
-  // ProvideSystemProfileMetrics() shouldn't be called initially.
-  EXPECT_FALSE(test_provider->provide_system_profile_metrics_called());
-  EXPECT_FALSE(service.persistent_system_profile_provided());
-
-  service.Start();
-
-  // Start should call ProvideSystemProfileMetrics().
-  EXPECT_TRUE(test_provider->provide_system_profile_metrics_called());
-  EXPECT_TRUE(service.persistent_system_profile_provided());
-  EXPECT_FALSE(service.persistent_system_profile_complete());
-}
-
 TEST_F(MetricsServiceTest, SplitRotation) {
   EnableMetricsReporting();
   TestMetricsServiceClient client;

components/metrics/ui/screen_info_metrics_provider.cc

@@ -66,17 +66,12 @@ ScreenInfoMetricsProvider::~ScreenInfoMetricsProvider() {
 
 void ScreenInfoMetricsProvider::ProvideSystemProfileMetrics(
     SystemProfileProto* system_profile_proto) {
-  // This may be called before the screen info has been initialized, such as
-  // when the persistent system profile gets filled in initially.
-  const base::Optional<gfx::Size> display_size = GetScreenSize();
-  if (!display_size.has_value())
-    return;
-
   SystemProfileProto::Hardware* hardware =
       system_profile_proto->mutable_hardware();
 
-  hardware->set_primary_screen_width(display_size->width());
-  hardware->set_primary_screen_height(display_size->height());
+  const gfx::Size display_size = GetScreenSize();
+  hardware->set_primary_screen_width(display_size.width());
+  hardware->set_primary_screen_height(display_size.height());
   hardware->set_primary_screen_scale_factor(GetScreenDeviceScaleFactor());
   hardware->set_screen_count(GetScreenCount());
 
@@ -85,11 +80,8 @@ void ScreenInfoMetricsProvider::ProvideSystemProfileMetrics(
 #endif
 }
 
-base::Optional<gfx::Size> ScreenInfoMetricsProvider::GetScreenSize() const {
-  auto* screen = display::Screen::GetScreen();
-  if (!screen)
-    return base::nullopt;
-  return base::make_optional(screen->GetPrimaryDisplay().GetSizeInPixel());
+gfx::Size ScreenInfoMetricsProvider::GetScreenSize() const {
+  return display::Screen::GetScreen()->GetPrimaryDisplay().GetSizeInPixel();
 }
 
 float ScreenInfoMetricsProvider::GetScreenDeviceScaleFactor() const {

components/metrics/ui/screen_info_metrics_provider.h

@@ -6,7 +6,6 @@
 #define COMPONENTS_METRICS_UI_SCREEN_INFO_METRICS_PROVIDER_H_
 
 #include "base/macros.h"
-#include "base/optional.h"
 #include "components/metrics/metrics_provider.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -25,8 +24,8 @@ class ScreenInfoMetricsProvider : public MetricsProvider {
  protected:
   // Exposed for the sake of mocking in test code.
 
-  // Returns the screen size for the primary monitor if available.
-  virtual base::Optional<gfx::Size> GetScreenSize() const;
+  // Returns the screen size for the primary monitor.
+  virtual gfx::Size GetScreenSize() const;
 
   // Returns the device scale factor for the primary monitor.
   virtual float GetScreenDeviceScaleFactor() const;

components/metrics/ui/screen_info_metrics_provider_unittest.cc

@@ -24,8 +24,8 @@ class TestScreenInfoMetricsProvider : public ScreenInfoMetricsProvider {
   ~TestScreenInfoMetricsProvider() override {}
 
  private:
-  base::Optional<gfx::Size> GetScreenSize() const override {
-    return base::make_optional(gfx::Size(kScreenWidth, kScreenHeight));
+  gfx::Size GetScreenSize() const override {
+    return gfx::Size(kScreenWidth, kScreenHeight);
   }
 
   float GetScreenDeviceScaleFactor() const override {

components/ukm/ukm_service.cc

@@ -78,8 +78,13 @@ UkmService::UkmService(PrefService* pref_service,
                        bool restrict_to_whitelist_entries)
     : pref_service_(pref_service),
       restrict_to_whitelist_entries_(restrict_to_whitelist_entries),
+      client_id_(0),
+      session_id_(0),
+      report_count_(0),
       client_(client),
-      reporting_service_(client, pref_service) {
+      reporting_service_(client, pref_service),
+      initialize_started_(false),
+      initialize_complete_(false) {
   DCHECK(pref_service_);
   DCHECK(client_);
   DVLOG(1) << "UkmService::Constructor";
@@ -126,7 +131,6 @@ void UkmService::EnableReporting() {
   if (reporting_service_.reporting_active())
     return;
 
-  log_creation_time_ = base::TimeTicks::Now();
   metrics_providers_.OnRecordingEnabled();
 
   if (!initialize_started_)
@@ -256,8 +260,8 @@ void UkmService::BuildAndStoreLog() {
   metrics::MetricsLog::RecordCoreSystemProfile(client_,
                                                report.mutable_system_profile());
 
-  metrics_providers_.ProvideSystemProfileMetricsWithLogCreationTime(
-      log_creation_time_, report.mutable_system_profile());
+  metrics_providers_.ProvideSystemProfileMetrics(
+      report.mutable_system_profile());
 
   std::string serialized_log;
   report.SerializeToString(&serialized_log);

components/ukm/ukm_service.h

@@ -128,13 +128,13 @@ class UkmService : public UkmRecorderImpl {
   bool restrict_to_whitelist_entries_;
 
   // The UKM client id stored in prefs.
-  uint64_t client_id_ = 0;
+  uint64_t client_id_;
 
   // The UKM session id stored in prefs.
-  int32_t session_id_ = 0;
+  int32_t session_id_;
 
   // The number of reports generated this session.
-  int32_t report_count_ = 0;
+  int32_t report_count_;
 
   // Used to interact with the embedder. Weak pointer; must outlive |this|
   // instance.
@@ -149,13 +149,11 @@ class UkmService : public UkmRecorderImpl {
   // The scheduler for determining when uploads should happen.
   std::unique_ptr<metrics::MetricsRotationScheduler> scheduler_;
 
-  base::TimeTicks log_creation_time_;
-
-  bool initialize_started_ = false;
-  bool initialize_complete_ = false;
-
   SEQUENCE_CHECKER(sequence_checker_);
 
+  bool initialize_started_;
+  bool initialize_complete_;
+
   // Weak pointers factory used to post task on different threads. All weak
   // pointers managed by this factory have the same lifetime as UkmService.
   base::WeakPtrFactory<UkmService> self_ptr_factory_{this};