Log operator code histogram on new metric log

chrome/browser/metrics/metrics_service.h

 // Copyright (c) 2012 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.
 
 // This file defines a service that collects information about the user
 // experience in order to help improve future versions of the app.
 
 #ifndef CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/user_metrics.h"
+#include "base/observer_list.h"
 #include "base/process/kill.h"
 #include "base/time/time.h"
 #include "chrome/browser/metrics/metrics_log.h"
 #include "chrome/browser/metrics/tracking_synchronizer_observer.h"
 #include "chrome/common/metrics/metrics_service_base.h"
 #include "chrome/installer/util/google_update_settings.h"
 #include "content/public/browser/browser_child_process_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/user_metrics.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 #if defined(OS_ANDROID)
 #include "chrome/browser/android/activity_type_ids.h"
 #elif defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/external_metrics.h"
 #endif
 
+class ChromeBrowserMetricsLogObserver;
 class MetricsReportingScheduler;
 class PrefService;
 class PrefRegistrySimple;
 class Profile;
 class TemplateURLService;
 
 namespace {
 class CrashesDOMHandler;
 class FlashDOMHandler;
 }
@@ skipping 52 matching lines @@
  private:
   friend class MetricsService;
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
 
   // This constructor is private specifically so as to control which code is
   // able to access it. New code that wishes to use it should be added as a
   // friend class.
   SyntheticTrialGroup(uint32 trial, uint32 group);
 };
 
+class MetricsLogObserver {

[Ilya Sherman, 2014/05/07 01:03:16]

nit: I think "MetricsServiceObserver" is more accurate, given where this class
is defined.  Also, could you please extract this class out to its own header
file?

[bolian, 2014/05/07 02:20:26]

Done.

+ public:
+  // Will be called when a new MetricsLog is created.
+  virtual void OnNewMetricsLog() = 0;

[Ilya Sherman, 2014/05/07 01:03:16]

nit: "OnDidCreateMetricsLog()" or something else involving a verb :)

[bolian, 2014/05/07 02:20:26]

Done.

+
+ protected:
+  MetricsLogObserver() {}
+  virtual ~MetricsLogObserver() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MetricsLogObserver);
+};
+
 class MetricsService
     : public chrome_browser_metrics::TrackingSynchronizerObserver,
       public content::BrowserChildProcessObserver,
       public content::NotificationObserver,
       public net::URLFetcherDelegate,
       public MetricsServiceBase {
  public:
   // The execution phase of the browser.
   enum ExecutionPhase {
     UNINITIALIZED_PHASE = 0,
@@ skipping 233 matching lines @@
 
   // If in_idle is true, sets idle_since_last_transmission to true.
   // If in_idle is false and idle_since_last_transmission_ is true, sets
   // idle_since_last_transmission to false and starts the timer (provided
   // starting the timer is permitted).
   void HandleIdleSinceLastTransmission(bool in_idle);
 
   // Set up client ID, session ID, etc.
   void InitializeMetricsState();
 
+  // Registers/Unregsiters |observer| to receive MetricsLog notifications.

[Ilya Sherman, 2014/05/07 01:03:16]

nit: "Un" -> "un"

[bolian, 2014/05/07 02:20:26]

Done.

+  void AddMetricsLogObserver(MetricsLogObserver* observer);
+  void RemoveMetricsLogObserver(MetricsLogObserver* observer);
+  void NotifyOnNewMetricsLog();
+
   // Schedule the next save of LocalState information.  This is called
   // automatically by the task that performs each save to schedule the next one.
   void ScheduleNextStateSave();
 
   // Save the LocalState information immediately. This should not be called by
   // anybody other than the scheduler to avoid doing too many writes. When you
   // make a change, call ScheduleNextStateSave() instead.
   void SaveLocalState();
 
   // Opens a new log for recording user experience metrics.
@@ skipping 201 matching lines @@
   // Execution phase the browser is in.
   static ExecutionPhase execution_phase_;
 
   // Reduntant marker to check that we completed our shutdown, and set the
   // exited-cleanly bit in the prefs.
   static ShutdownCleanliness clean_shutdown_status_;
 
   // Field trial groups that map to Chrome configuration states.
   SyntheticTrialGroups synthetic_trial_groups_;
 
+  // Observers of MetricsLog.
+  ObserverList<MetricsLogObserver> metrics_log_observers_;
+
+  friend class MetricsServiceHelper;
+
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, IsPluginProcess);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
                            PermutedEntropyCacheClearedWhenLowEntropyReset);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
+  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, MetricsLogObserver);
 
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
-// This class limits and documents access to the IsMetricsReportingEnabled() and
-// IsCrashReportingEnabled() methods. Since these methods are private, each user
-// has to be explicitly declared as a 'friend' below.
+// This class limits and documents access to metrics service helper methods.
+// Since these methods are private, each user has to be explicitly declared
+// as a 'friend' below.
 class MetricsServiceHelper {
  private:
   friend bool prerender::IsOmniboxEnabled(Profile* profile);
   friend class ChromeRenderMessageFilter;
+  friend class ::ChromeBrowserMetricsLogObserver;

[Ilya Sherman, 2014/05/07 01:03:16]

nit: Alphabetically, this should come before line 625 (though the namespaces
make it weird).

[bolian, 2014/05/07 02:20:26]

Done.

   friend class ::CrashesDOMHandler;
   friend class extensions::ExtensionDownloader;
   friend class extensions::ManifestFetchData;
   friend class extensions::MetricsPrivateGetIsCrashReportingEnabledFunction;
   friend class ::FlashDOMHandler;
   friend class system_logs::ChromeInternalLogSource;
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, MetricsReportingEnabled);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, CrashReportingEnabled);
 
   // Returns true if prefs::kMetricsReportingEnabled is set.
   // TODO(asvitkine): Consolidate the method in MetricsStateManager.
   // TODO(asvitkine): This function does not report the correct value on
   // Android and ChromeOS, see http://crbug.com/362192.
   static bool IsMetricsReportingEnabled();
 
   // Returns true if crash reporting is enabled.  This is set at the platform
   // level for Android and ChromeOS, and otherwise is the same as
   // IsMetricsReportingEnabled for desktop Chrome.
   static bool IsCrashReportingEnabled();
 
+  // Registers/Unregsiters |observer| to receive MetricsLog notifications
+  // from metric service.
+  static void AddMetricsLogObserver(MetricsLogObserver* observer);
+  static void RemoveMetricsLogObserver(MetricsLogObserver* observer);
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(MetricsServiceHelper);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_SERVICE_H_