Send UMA stability stats in a separate UMA log on startup.

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_
 
@@ skipping 93 matching lines @@
     UNINITIALIZED_PHASE = 0,
     START_METRICS_RECORDING = 100,
     CREATE_PROFILE = 200,
     STARTUP_TIMEBOMB_ARM = 300,
     THREAD_WATCHER_START = 400,
     MAIN_MESSAGE_LOOP_RUN = 500,
     SHUTDOWN_TIMEBOMB_ARM = 600,
     SHUTDOWN_COMPLETE = 700,
   };
 
+  enum ReportingState {
+    REPORTING_ENABLED,
+    REPORTING_DISABLED,
+  };
+
   MetricsService();
   virtual ~MetricsService();
 
+  // Initializes metrics recording state. Updates various bookkeeping values in
+  // prefs and sets up the scheduler. This is a separate function rather than
+  // being done by the constructor so that field trials could be created before
+  // this is run. Takes |reporting_state| parameter which specifies whether UMA
+  // is enabled.
+  void InitializeMetricsRecordingState(ReportingState reporting_state);
+
   // Starts the metrics system, turning on recording and uploading of metrics.
   // Should be called when starting up with metrics enabled, or when metrics
   // are turned on.
   void Start();
 
   // Starts the metrics system in a special test-only mode. Metrics won't ever
   // be uploaded or persisted in this mode, but metrics will be recorded in
   // memory.
   void StartRecordingForTests();
 
@@ skipping 19 matching lines @@
   //
   // If |reporting_will_be_enabled| is true, this method returns an entropy
   // provider that has a high source of entropy, partially based on the client
   // ID. Otherwise, an entropy provider that is based on a low entropy source
   // is returned.
   //
   // Note that this reporting state can not be checked by reporting_active()
   // because this method may need to be called before the MetricsService needs
   // to be started.
   scoped_ptr<const base::FieldTrial::EntropyProvider> CreateEntropyProvider(
-      bool reporting_will_be_enabled);
+      ReportingState reporting_state);
 
   // Force the client ID to be generated. This is useful in case it's needed
   // before recording.
   void ForceClientIdCreation();
 
   // At startup, prefs needs to be called with a list of all the pref names and
   // types we'll be using.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
   // Set up notifications which indicate that a user is performing work. This is
@@ skipping 79 matching lines @@
   // registered at a time for a given trial_name. Only the last group name that
   // is registered for a given trial name will be recorded. The values passed
   // in must not correspond to any real field trial in the code.
   // To use this method, SyntheticTrialGroup should friend your class.
   void RegisterSyntheticFieldTrial(const SyntheticTrialGroup& trial_group);
 
  private:
   // The MetricsService has a lifecycle that is stored as a state.
   // See metrics_service.cc for description of this lifecycle.
   enum State {
-    INITIALIZED,            // Constructor was called.
-    INIT_TASK_SCHEDULED,    // Waiting for deferred init tasks to complete.
-    INIT_TASK_DONE,         // Waiting for timer to send initial log.
-    INITIAL_LOG_READY,      // Initial log generated, and waiting for reply.
-    SENDING_OLD_LOGS,       // Sending unsent logs from previous session.
-    SENDING_CURRENT_LOGS,   // Sending standard current logs as they acrue.
+    INITIALIZED,                    // Constructor was called.
+    INIT_TASK_SCHEDULED,            // Waiting for deferred init task to finish.
+    INIT_TASK_DONE,                 // Waiting for timer to send initial log.
+    SENDING_INITIAL_STABILITY_LOG,  // Initial stability log being sent.
+    SENDING_INITIAL_METRICS_LOG,    // Initial metrics log being sent.
+    SENDING_OLD_LOGS,               // Sending unsent logs from last session.
+    SENDING_CURRENT_LOGS,           // Sending ongoing logs as they accrue.
   };
 
   enum ShutdownCleanliness {
     CLEANLY_SHUTDOWN = 0xdeadbeef,
     NEED_TO_SHUTDOWN = ~CLEANLY_SHUTDOWN
   };
 
   // Designates which entropy source was returned from this MetricsService.
   // This is used for testing to validate that we return the correct source
   // depending on the state of the service.
@@ skipping 70 matching lines @@
   void EnableRecording();
   void DisableRecording();
 
   // 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();
+  void InitializeMetricsState(ReportingState reporting_state);
 
   // Generates a new client ID to use to identify self to metrics server.
   static std::string GenerateClientID();
 
   // 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
@@ skipping 23 matching lines @@
   // Callbacks for various stages of final log info collection. Do not call
   // these directly.
   void OnMemoryDetailCollectionDone();
   void OnHistogramSynchronizationDone();
   void OnFinalLogInfoCollectionDone();
 
   // Either closes the current log or creates and closes the initial log
   // (depending on |state_|), and stages it for upload.
   void StageNewLog();
 
-  // Record stats, client ID, Session ID, etc. in a special "first" log.
-  void PrepareInitialLog();
+  // Prepares the initial stability log, based on the saved system profile from
+  // a previous session with updated stability stats (only) and stages it for
+  // upload.

[Ilya Sherman, 2013/12/07 06:51:54]

nit: Sorry to super nitpick, but I still find this comment not entirely clear. 
A suggested rephrasing, feel free to further refine:

"Prepares the initial stability log, which is only logged when the previous run
of Chrome crashed.  This log contains any stability metrics left over from that
previous run, and only these stability metrics.  It uses the system profile from
the previous session."

[Alexei Svitkine (slow), 2013/12/09 21:17:02]

Done.

+  void PrepareInitialStabilityLog();
+
+  // Prepares the initial metrics log, which includes startup histograms and
+  // profiler data, as well as incremental stability-related metrics.
+  void PrepareInitialMetricsLog(MetricsLog::LogType log_type);
 
   // Uploads the currently staged log (which must be non-null).
   void SendStagedLog();
 
   // Prepared the staged log to be passed to the server. Upon return,
   // current_fetch_ should be reset with its upload data set to a compressed
   // copy of the staged log.
   void PrepareFetchWithStagedLog();
 
   // Implementation of net::URLFetcherDelegate. Called after transmission
@@ skipping 72 matching lines @@
   // WiFi adapter, etc.  For non Chrome OS hosts, this will be an
   // empty string.
   std::string hardware_class_;
 
   // The list of plugins which was retrieved on the file thread.
   std::vector<content::WebPluginInfo> plugins_;
 
   // Google Update statistics, which were retrieved on a blocking pool thread.
   GoogleUpdateMetrics google_update_metrics_;
 
-  // The initial log, used to record startup metrics.
-  scoped_ptr<MetricsLog> initial_log_;
+  // The initial metrics log, used to record startup metrics (histograms and
+  // profiler data). Note that if a crash occurred in the previous session, an
+  // initial stability log may be sent before this.
+  scoped_ptr<MetricsLog> initial_metrics_log_;
 
   // The outstanding transmission appears as a URL Fetch operation.
   scoped_ptr<net::URLFetcher> current_fetch_;
 
   // The TCP/UDP echo server to collect network connectivity stats.
   std::string network_stats_server_;
 
   // The HTTP pipelining test server.
   std::string http_pipelining_test_server_;
 
@@ skipping 82 matching lines @@
   friend class extensions::ExtensionDownloader;
   friend class extensions::ManifestFetchData;
 
   // Returns true if prefs::kMetricsReportingEnabled is set.
   static bool IsMetricsReportingEnabled();
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MetricsServiceHelper);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_SERVICE_H_