Remove MetricsServiceObserver in favor of MetricsProvider.

The only user of this interface has been folded into
NetworkMetricsProvider.

BUG=409872

Review URL: https://codereview.chromium.org/532623003

Cr-Commit-Position: refs/heads/master@{#293149}

chrome/browser/chrome_browser_metrics_service_observer.cc

-// Copyright 2014 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/chrome_browser_metrics_service_observer.h"
-
-#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
-#include "net/base/network_change_notifier.h"
-
-ChromeBrowserMetricsServiceObserver::ChromeBrowserMetricsServiceObserver() {
-  ChromeMetricsServiceAccessor::AddMetricsServiceObserver(this);
-}
-
-ChromeBrowserMetricsServiceObserver::~ChromeBrowserMetricsServiceObserver() {
-  ChromeMetricsServiceAccessor::RemoveMetricsServiceObserver(this);
-}
-
-void ChromeBrowserMetricsServiceObserver::OnDidCreateMetricsLog() {
-  net::NetworkChangeNotifier::LogOperatorCodeHistogram(
-      net::NetworkChangeNotifier::GetConnectionType());
-}

chrome/browser/chrome_browser_metrics_service_observer.h

-// Copyright 2014 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 CHROME_BROWSER_CHROME_BROWSER_METRICS_SERVICE_OBSERVER_H_
-#define CHROME_BROWSER_CHROME_BROWSER_METRICS_SERVICE_OBSERVER_H_
-
-#include "components/metrics/metrics_service_observer.h"
-
-// ChromeBrowserMetricsServiceObserver receives notifications when the metrics
-// service creates a new metrics log.
-class ChromeBrowserMetricsServiceObserver
-    : public metrics::MetricsServiceObserver {
- public:
-  ChromeBrowserMetricsServiceObserver();
-  virtual ~ChromeBrowserMetricsServiceObserver();
-
-  // MetricsServiceObserver:
-  virtual void OnDidCreateMetricsLog() OVERRIDE;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMetricsServiceObserver);
-};
-
-#endif  // CHROME_BROWSER_CHROME_BROWSER_METRICS_SERVICE_OBSERVER_H_

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

@@ -17,7 +17,6 @@
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_browser_main.h"
-#include "chrome/browser/chrome_browser_metrics_service_observer.h"
 #include "chrome/browser/mac/bluetooth_utility.h"
 #include "chrome/browser/pref_service_flags_storage.h"
 #include "chrome/browser/shell_integration.h"
@@ -234,12 +233,6 @@ void ChromeBrowserMainExtraPartsMetrics::PostBrowserStart() {
       FROM_HERE,
       base::Bind(&RecordStartupMetricsOnBlockingPool),
       base::TimeDelta::FromSeconds(kStartupMetricsGatheringDelaySeconds));
-
-  // Create the metrics log observer.
-  // We only need this for Android for now.
-#if defined(ANDROID)
-  metrics_service_observer_.reset(new ChromeBrowserMetricsServiceObserver());
-#endif
 }
 
 namespace chrome {

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.h

@@ -11,7 +11,6 @@
 #include "chrome/browser/chrome_browser_main_extra_parts.h"
 
 class ChromeBrowserMainParts;
-class ChromeBrowserMetricsServiceObserver;
 
 namespace chrome {
 void AddMetricsExtraParts(ChromeBrowserMainParts* main_parts);
@@ -28,9 +27,6 @@ class ChromeBrowserMainExtraPartsMetrics : public ChromeBrowserMainExtraParts {
   virtual void PostBrowserStart() OVERRIDE;
 
  private:
-  // Observe and log histograms on new metric logs.
-  scoped_ptr<ChromeBrowserMetricsServiceObserver> metrics_service_observer_;
-
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainExtraPartsMetrics);
 };
 

chrome/browser/metrics/chrome_metrics_service_accessor.h

@@ -12,7 +12,6 @@
 #include "base/macros.h"
 #include "chrome/browser/metrics/metrics_service_accessor.h"
 
-class ChromeBrowserMetricsServiceObserver;
 class Profile;
 
 namespace {
@@ -40,7 +39,6 @@ class ChromeInternalLogSource;
 class ChromeMetricsServiceAccessor : public MetricsServiceAccessor {
  private:
   friend bool prerender::IsOmniboxEnabled(Profile* profile);
-  friend class ::ChromeBrowserMetricsServiceObserver;
   friend class ChromeRenderMessageFilter;
   friend class ::CrashesDOMHandler;
   friend class DataReductionProxyChromeSettings;

chrome/browser/metrics/metrics_service_accessor.cc

@@ -4,30 +4,12 @@
 
 #include "chrome/browser/metrics/metrics_service_accessor.h"
 
-#include "chrome/browser/browser_process.h"
 #include "components/metrics/metrics_service.h"
-#include "components/metrics/metrics_service_observer.h"
 
 // TODO(asvitkine): Remove when this class is moved to metrics namespace.
 using metrics::MetricsService;
-using metrics::MetricsServiceObserver;
 using metrics::SyntheticTrialGroup;
 
-// static
-void MetricsServiceAccessor::AddMetricsServiceObserver(
-    MetricsServiceObserver* observer) {
-  MetricsService* metrics_service = g_browser_process->metrics_service();
-  if (metrics_service)
-    metrics_service->AddObserver(observer);
-}
-
-void MetricsServiceAccessor::RemoveMetricsServiceObserver(
-    MetricsServiceObserver* observer) {
-  MetricsService* metrics_service = g_browser_process->metrics_service();
-  if (metrics_service)
-    metrics_service->RemoveObserver(observer);
-}
-
 // static
 bool MetricsServiceAccessor::RegisterSyntheticFieldTrial(
     MetricsService* metrics_service,

chrome/browser/metrics/metrics_service_accessor.h

@@ -6,13 +6,11 @@
 #define CHROME_BROWSER_METRICS_METRICS_SERVICE_ACCESSOR_H_
 
 #include <stdint.h>
-#include <string>
 
 #include "base/macros.h"
 
 namespace metrics {
 class MetricsService;
-class MetricsServiceObserver;
 }
 
 // This class limits and documents access to metrics service helper methods.
@@ -24,13 +22,6 @@ class MetricsServiceAccessor {
   // disallow instantiation.
   MetricsServiceAccessor() {}
 
-  // Registers/unregisters |observer| to receive MetricsLog notifications
-  // from metrics service.
-  static void AddMetricsServiceObserver(
-      metrics::MetricsServiceObserver* observer);
-  static void RemoveMetricsServiceObserver(
-      metrics::MetricsServiceObserver* observer);
-
   // Registers the specified synthetic field trial (identified by a hash of the
   // trial name and group name) with |metrics_service|, if the service is not
   // NULL, returning true on success.

chrome/browser/metrics/network_metrics_provider.cc

@@ -4,6 +4,9 @@
 
 #include "chrome/browser/metrics/network_metrics_provider.h"
 
+#include <string>
+#include <vector>
+
 #include "base/compiler_specific.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
@@ -32,6 +35,11 @@ NetworkMetricsProvider::~NetworkMetricsProvider() {
   net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
 }
 
+void NetworkMetricsProvider::OnDidCreateMetricsLog() {
+  net::NetworkChangeNotifier::LogOperatorCodeHistogram(
+      net::NetworkChangeNotifier::GetConnectionType());
+}
+
 void NetworkMetricsProvider::ProvideSystemProfileMetrics(
     SystemProfileProto* system_profile) {
   SystemProfileProto::Network* network = system_profile->mutable_network();

chrome/browser/metrics/network_metrics_provider.h

@@ -23,7 +23,9 @@ class NetworkMetricsProvider
   NetworkMetricsProvider();
   virtual ~NetworkMetricsProvider();
 
+ private:
   // metrics::MetricsProvider:
+  virtual void OnDidCreateMetricsLog() OVERRIDE;
   virtual void ProvideSystemProfileMetrics(
       metrics::SystemProfileProto* system_profile) OVERRIDE;
 
@@ -31,7 +33,6 @@ class NetworkMetricsProvider
   virtual void OnConnectionTypeChanged(
       net::NetworkChangeNotifier::ConnectionType type) OVERRIDE;
 
- private:
   metrics::SystemProfileProto::Network::ConnectionType
   GetConnectionType() const;
   metrics::SystemProfileProto::Network::WifiPHYLayerProtocol

chrome/chrome_browser.gypi

@@ -244,8 +244,6 @@
       'browser/chrome_browser_main_mac.mm',
       'browser/chrome_browser_main_win.cc',
       'browser/chrome_browser_main_win.h',
-      'browser/chrome_browser_metrics_service_observer.cc',
-      'browser/chrome_browser_metrics_service_observer.h',
       'browser/chrome_content_browser_client.cc',
       'browser/chrome_content_browser_client.h',
       'browser/chrome_content_browser_client_parts.h',

components/metrics.gypi

@@ -43,8 +43,6 @@
         'metrics/metrics_service.cc',
         'metrics/metrics_service.h',
         'metrics/metrics_service_client.h',
-        'metrics/metrics_service_observer.cc',
-        'metrics/metrics_service_observer.h',
         'metrics/metrics_state_manager.cc',
         'metrics/metrics_state_manager.h',
         'metrics/metrics_switches.cc',

components/metrics/BUILD.gn

@@ -30,8 +30,6 @@ source_set("metrics") {
     "metrics_service.cc",
     "metrics_service.h",
     "metrics_service_client.h",
-    "metrics_service_observer.cc",
-    "metrics_service_observer.h",
     "metrics_state_manager.cc",
     "metrics_state_manager.h",
     "metrics_switches.cc",

components/metrics/metrics_service.cc

@@ -666,20 +666,8 @@ void MetricsService::GetUptimes(PrefService* pref,
   }
 }
 
-void MetricsService::AddObserver(MetricsServiceObserver* observer) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  observers_.AddObserver(observer);
-}
-
-void MetricsService::RemoveObserver(MetricsServiceObserver* observer) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  observers_.RemoveObserver(observer);
-}
-
 void MetricsService::NotifyOnDidCreateMetricsLog() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  FOR_EACH_OBSERVER(
-      MetricsServiceObserver, observers_, OnDidCreateMetricsLog());
+  DCHECK(IsSingleThreaded());
   for (size_t i = 0; i < metrics_providers_.size(); ++i)
     metrics_providers_[i]->OnDidCreateMetricsLog();
 }

components/metrics/metrics_service.h

@@ -21,14 +21,10 @@
 #include "base/metrics/histogram_flattener.h"
 #include "base/metrics/histogram_snapshot_manager.h"
 #include "base/metrics/user_metrics.h"
-#include "base/observer_list.h"
-#include "base/strings/string16.h"
-#include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_provider.h"
-#include "components/metrics/metrics_service_observer.h"
 #include "components/variations/active_field_trials.h"
 
 class MetricsServiceAccessor;
@@ -283,9 +279,7 @@ class MetricsService : public base::HistogramFlattener {
   // Set up client ID, session ID, etc.
   void InitializeMetricsState();
 
-  // Registers/unregisters |observer| to receive MetricsLog notifications.
-  void AddObserver(MetricsServiceObserver* observer);
-  void RemoveObserver(MetricsServiceObserver* observer);
+  // Notifies providers when a new metrics log is created.
   void NotifyOnDidCreateMetricsLog();
 
   // Schedule the next save of LocalState information.  This is called
@@ -446,6 +440,9 @@ class MetricsService : public base::HistogramFlattener {
   // Stores the time of the last call to |GetUptimes()|.
   base::TimeTicks last_updated_time_;
 
+  // Field trial groups that map to Chrome configuration states.
+  SyntheticTrialGroups synthetic_trial_groups_;
+
   // Execution phase the browser is in.
   static ExecutionPhase execution_phase_;
 
@@ -453,18 +450,9 @@ class MetricsService : public base::HistogramFlattener {
   // exited-cleanly bit in the prefs.
   static ShutdownCleanliness clean_shutdown_status_;
 
-  // Field trial groups that map to Chrome configuration states.
-  SyntheticTrialGroups synthetic_trial_groups_;
-
-  ObserverList<MetricsServiceObserver> observers_;
-
-  // Confirms single-threaded access to |observers_| in debug builds.
-  base::ThreadChecker thread_checker_;
-
   friend class ::MetricsServiceAccessor;
 
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, IsPluginProcess);
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, MetricsServiceObserver);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
                            PermutedEntropyCacheClearedWhenLowEntropyReset);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);

components/metrics/metrics_service_observer.cc

-// Copyright 2014 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 "components/metrics/metrics_service_observer.h"
-
-namespace metrics {
-
-MetricsServiceObserver::MetricsServiceObserver() {
-}
-
-MetricsServiceObserver::~MetricsServiceObserver() {
-}
-
-}  // namespace metrics

components/metrics/metrics_service_observer.h

-// Copyright 2014 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 COMPONENTS_METRICS_METRICS_SERVICE_OBSERVER_H_
-#define COMPONENTS_METRICS_METRICS_SERVICE_OBSERVER_H_
-
-#include "base/macros.h"
-
-namespace metrics {
-
-// MetricsServiceObserver receives notifications from MetricsService.
-// An observer must be added, removed, and notified on the same thread.
-class MetricsServiceObserver {
- public:
-  // Called when a new MetricsLog is created.
-  virtual void OnDidCreateMetricsLog() = 0;
-
- protected:
-  MetricsServiceObserver();
-  virtual ~MetricsServiceObserver();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(MetricsServiceObserver);
-};
-
-}  // namespace metrics
-
-#endif  // COMPONENTS_METRICS_METRICS_SERVICE_OBSERVER_H_

components/metrics/metrics_service_unittest.cc

@@ -15,7 +15,6 @@
 #include "components/metrics/compression_utils.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_pref_names.h"
-#include "components/metrics/metrics_service_observer.h"
 #include "components/metrics/metrics_state_manager.h"
 #include "components/metrics/test_metrics_service_client.h"
 #include "components/variations/metrics_util.h"
@@ -130,22 +129,6 @@ class MetricsServiceTest : public testing::Test {
   DISALLOW_COPY_AND_ASSIGN(MetricsServiceTest);
 };
 
-class TestMetricsServiceObserver : public MetricsServiceObserver {
- public:
-  TestMetricsServiceObserver(): observed_(0) {}
-  virtual ~TestMetricsServiceObserver() {}
-
-  virtual void OnDidCreateMetricsLog() OVERRIDE {
-    ++observed_;
-  }
-  int observed() const { return observed_; }
-
- private:
-  int observed_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestMetricsServiceObserver);
-};
-
 }  // namespace
 
 TEST_F(MetricsServiceTest, InitialStabilityLogAfterCleanShutDown) {
@@ -283,36 +266,4 @@ TEST_F(MetricsServiceTest, RegisterSyntheticTrial) {
   service.log_manager_.FinishCurrentLog();
 }
 
-TEST_F(MetricsServiceTest, MetricsServiceObserver) {
-  metrics::TestMetricsServiceClient client;
-  MetricsService service(GetMetricsStateManager(), &client, GetLocalState());
-  TestMetricsServiceObserver observer1;
-  TestMetricsServiceObserver observer2;
-
-  service.AddObserver(&observer1);
-  EXPECT_EQ(0, observer1.observed());
-  EXPECT_EQ(0, observer2.observed());
-
-  service.OpenNewLog();
-  EXPECT_EQ(1, observer1.observed());
-  EXPECT_EQ(0, observer2.observed());
-  service.log_manager_.FinishCurrentLog();
-
-  service.AddObserver(&observer2);
-
-  service.OpenNewLog();
-  EXPECT_EQ(2, observer1.observed());
-  EXPECT_EQ(1, observer2.observed());
-  service.log_manager_.FinishCurrentLog();
-
-  service.RemoveObserver(&observer1);
-
-  service.OpenNewLog();
-  EXPECT_EQ(2, observer1.observed());
-  EXPECT_EQ(2, observer2.observed());
-  service.log_manager_.FinishCurrentLog();
-
-  service.RemoveObserver(&observer2);
-}
-
 }  // namespace metrics