Add Startup Timing to CPM

chrome/browser/performance_monitor/startup_timer.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.
+
+#ifndef CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_
+#define CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_
+
+#include "base/time.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+namespace performance_monitor {
+
+// This class is responsible for recording the startup and session restore times
+// (if applicable) for PerformanceMonitor. This allows us to initialize this
+// relatively small object early in the startup process, and start the whole of
+// PerformanceMonitor at a later time. StartupTimer will record the times and
+// insert them into PerformanceMonitor's database.
+class StartupTimer : public content::NotificationObserver {
+ public:
+  // Indicates the type of startup; i.e. either a normal startup or a testing
+  // environment.
+  enum StartupType {
+    STARTUP_NORMAL,
+    STARTUP_TEST
+  };
+
+  StartupTimer();
+  virtual ~StartupTimer();
+
+  // Inform StartupTimer that the startup process has been completed; stop the
+  // timer. Returns false if the timer has already stopped.
+  bool SignalStartupComplete(StartupType startup_type);
+
+  // Pauses the timer until UnpauseTimer() is called; any time spent within a
+  // pause does not count towards the measured startup time. This will DCHECK if
+  // PauseTimer() is called while paused or UnpauseTimer() is called while
+  // unpaused.
+  static void PauseTimer();
+  static void UnpauseTimer();
+
+  // content::NotificationObserver
+  // We keep track of whether or not PerformanceMonitor has been started via
+  // the PERFORMANCE_MONITOR_INITIALIZED notification; we need to know this so
+  // we know when to insert startup data into the database. We either insert
+  // data as we gather it (if PerformanceMonitor is started prior to data
+  // collection) or at the notification (if PerformanceMonitor is started
+  // later).
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  static void SetElapsedSessionRestoreTime(
+      const base::TimeDelta& elapsed_session_restore_time);
+
+ private:
+  // Insert the elapsed time measures into PerformanceMonitor's database.
+  void InsertElapsedStartupTime();
+  void InsertElapsedSessionRestoreTime();
+
+  // The time at which the startup process begins (the creation of
+  // ChromeBrowserMain).
+  base::TimeTicks startup_begin_;
+
+  // The time at which the timer was most recently paused, or null if the timer
+  // is not currently paused.
+  base::TimeTicks pause_started_;
+
+  // The total duration for which the timer has been paused.
+  base::TimeDelta total_pause_;
+
+  // A flag of whether or not this was a "normal" startup (e.g. whether or not
+  // this was in a testing environment, which would change the startup time
+  // values). If it is not a normal startup, we use a different metric.
+  StartupType startup_type_;
+
+  // The total duration of the startup process, minus any pauses.
+  base::TimeDelta elapsed_startup_time_;
+
+  // The total duration of the session restore(s), if any occurred. This is
+  // independent of the startup time, because:
+  // - If the user has auto-restore on, the restore is synchronous, and we pause
+  //   the startup timer during the session restore; the restore will not
+  //   interfere with startup timing.
+  // - If Chrome crashed and the user chooses to restore the crashed session,
+  //   then the startup is already completed; the restore will not interfere
+  //   with startup timing.
+  std::vector<base::TimeDelta> elapsed_session_restore_times_;
+
+  // Flag whether or not PerformanceMonitor has been fully started.
+  bool performance_monitor_initialized_;
+
+  content::NotificationRegistrar registrar_;
+
+  // The singleton of this class.
+  static StartupTimer* g_startup_timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(StartupTimer);
+};
+
+}  // namespace performance_monitor
+
+#endif  // CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_