Add Startup Timing to CPM

Add in support for timing chrome's startup and session restore times.

BUG=130212
TEST=Included


Review URL: https://chromiumcodereview.appspot.com/10834015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150881 0039d316-1c4b-4281-b951-d872f2087c98

16 files changed, 439 insertions, 9 deletions

diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 4b07ad4..d8eac6e 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -56,6 +56,7 @@
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/notifications/desktop_notification_service_factory.h"
 #include "chrome/browser/page_cycler/page_cycler.h"
+#include "chrome/browser/performance_monitor/startup_timer.h"
 #include "chrome/browser/plugin_prefs.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/pref_value_store.h"
@@ -498,6 +499,7 @@ ChromeBrowserMainParts::ChromeBrowserMainParts(
       result_code_(content::RESULT_CODE_NORMAL_EXIT),
       startup_watcher_(new StartupTimeBomb()),
       shutdown_watcher_(new ShutdownWatcherHelper()),
+      startup_timer_(new performance_monitor::StartupTimer()),
       browser_field_trials_(parameters.command_line),
       record_search_engine_(false),
       translate_manager_(NULL),
@@ -1383,6 +1385,10 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
   PostBrowserStart();
 
   if (parameters().ui_task) {
+    // We end the startup timer here if we have parameters to run, because we
+    // never start to run the main loop (where we normally stop the timer).
+    startup_timer_->SignalStartupComplete(
+        performance_monitor::StartupTimer::STARTUP_TEST);
     parameters().ui_task->Run();
     delete parameters().ui_task;
     run_message_loop_ = false;
@@ -1403,10 +1409,13 @@ bool ChromeBrowserMainParts::MainMessageLoopRun(int* result_code) {
   if (!run_message_loop_)
     return true;  // Don't run the default message loop.
 
-  // This should be invoked as close to the start of the browser's
+  // These should be invoked as close to the start of the browser's
   // UI thread message loop as possible to get a stable measurement
   // across versions.
   RecordBrowserStartupTime();
+  startup_timer_->SignalStartupComplete(
+      performance_monitor::StartupTimer::STARTUP_NORMAL);
+
   DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
 #if !defined(USE_AURA) && defined(TOOLKIT_VIEWS)
   views::AcceleratorHandler accelerator_handler;
diff --git a/chrome/browser/chrome_browser_main.h b/chrome/browser/chrome_browser_main.h
index 1b16d9c..c820c16 100644
--- a/chrome/browser/chrome_browser_main.h
+++ b/chrome/browser/chrome_browser_main.h
@@ -44,6 +44,10 @@ namespace content {
 struct MainFunctionParams;
 }
 
+namespace performance_monitor {
+class StartupTimer;
+}
+
 class ChromeBrowserMainParts : public content::BrowserMainParts {
  public:
   virtual ~ChromeBrowserMainParts();
@@ -132,6 +136,11 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
   // it is destroyed last.
   scoped_ptr<ShutdownWatcherHelper> shutdown_watcher_;
 
+  // A timer to hold data regarding startup and session restore times for
+  // PerformanceMonitor so that we don't have to start the entire
+  // PerformanceMonitor at browser startup.
+  scoped_ptr<performance_monitor::StartupTimer> startup_timer_;
+
   // Creating this object starts tracking the creation and deletion of Task
   // instance. This MUST be done before main_message_loop, so that it is
   // destroyed after the main_message_loop.
diff --git a/chrome/browser/performance_monitor/constants.cc b/chrome/browser/performance_monitor/constants.cc
index 27d660b..3c167cc 100644
--- a/chrome/browser/performance_monitor/constants.cc
+++ b/chrome/browser/performance_monitor/constants.cc
@@ -53,4 +53,25 @@ const char kMetricSharedMemoryUsageDescription[] =
 const char kMetricSharedMemoryUsageUnits[] = "bytes";
 const double kMetricSharedMemoryUsageTickSize = 10000000.0;
 
+// Startup Time
+const char kMetricStartupTimeName[] = "Startup Time";
+const char kMetricStartupTimeDescription[] =
+    "The startup time measured in microseconds";
+const char kMetricStartupTimeUnits[] = "microseconds";
+const double kMetricStartupTimeTickSize = 5000000;
+
+// Test Startup Time
+const char kMetricTestStartupTimeName[] = "Test Startup Time";
+const char kMetricTestStartupTimeDescription[] =
+    "The startup time of test startups measured in microseconds";
+const char kMetricTestStartupTimeUnits[] = "microseconds";
+const double kMetricTestStartupTimeTickSize = 5000000;
+
+// Session Restore Time
+const char kMetricSessionRestoreTimeName[] = "Session Restore Time";
+const char kMetricSessionRestoreTimeDescription[] =
+    "The session restore time measured in microseconds";
+const char kMetricSessionRestoreTimeUnits[] = "microseconds";
+const double kMetricSessionRestoreTimeTickSize = 5000000;
+
 }  // namespace performance_monitor
diff --git a/chrome/browser/performance_monitor/constants.h b/chrome/browser/performance_monitor/constants.h
index 9065538..dbf153d 100644
--- a/chrome/browser/performance_monitor/constants.h
+++ b/chrome/browser/performance_monitor/constants.h
@@ -24,15 +24,32 @@ extern const char kMetricCPUUsageName[];
 extern const char kMetricCPUUsageDescription[];
 extern const char kMetricCPUUsageUnits[];
 extern const double kMetricCPUUsageTickSize;
+
 extern const char kMetricPrivateMemoryUsageName[];
 extern const char kMetricPrivateMemoryUsageDescription[];
 extern const char kMetricPrivateMemoryUsageUnits[];
 extern const double kMetricPrivateMemoryUsageTickSize;
+
 extern const char kMetricSharedMemoryUsageName[];
 extern const char kMetricSharedMemoryUsageDescription[];
 extern const char kMetricSharedMemoryUsageUnits[];
 extern const double kMetricSharedMemoryUsageTickSize;
 
+extern const char kMetricStartupTimeName[];
+extern const char kMetricStartupTimeDescription[];
+extern const char kMetricStartupTimeUnits[];
+extern const double kMetricStartupTimeTickSize;
+
+extern const char kMetricTestStartupTimeName[];
+extern const char kMetricTestStartupTimeDescription[];
+extern const char kMetricTestStartupTimeUnits[];
+extern const double kMetricTestStartupTimeTickSize;
+
+extern const char kMetricSessionRestoreTimeName[];
+extern const char kMetricSessionRestoreTimeDescription[];
+extern const char kMetricSessionRestoreTimeUnits[];
+extern const double kMetricSessionRestoreTimeTickSize;
+
 }  // namespace performance_monitor
 
 #endif  // CHROME_BROWSER_PERFORMANCE_MONITOR_CONSTANTS_H_
diff --git a/chrome/browser/performance_monitor/metric_details.cc b/chrome/browser/performance_monitor/metric_details.cc
index 2767728..613bfdf 100644
--- a/chrome/browser/performance_monitor/metric_details.cc
+++ b/chrome/browser/performance_monitor/metric_details.cc
@@ -31,6 +31,24 @@ const MetricDetails kMetricDetailsList[] = {
     kMetricSharedMemoryUsageUnits,
     kMetricSharedMemoryUsageTickSize
   },
+  {
+    kMetricStartupTimeName,
+    kMetricStartupTimeDescription,
+    kMetricStartupTimeUnits,
+    kMetricStartupTimeTickSize
+  },
+  {
+    kMetricTestStartupTimeName,
+    kMetricTestStartupTimeDescription,
+    kMetricTestStartupTimeUnits,
+    kMetricTestStartupTimeTickSize
+  },
+  {
+    kMetricSessionRestoreTimeName,
+    kMetricSessionRestoreTimeDescription,
+    kMetricSessionRestoreTimeUnits,
+    kMetricSessionRestoreTimeTickSize
+  }
 };
 COMPILE_ASSERT(ARRAYSIZE_UNSAFE(kMetricDetailsList) == METRIC_NUMBER_OF_METRICS,
                metric_names_incorrect_size);
diff --git a/chrome/browser/performance_monitor/metric_details.h b/chrome/browser/performance_monitor/metric_details.h
index 10f1ff0..ba0f357 100644
--- a/chrome/browser/performance_monitor/metric_details.h
+++ b/chrome/browser/performance_monitor/metric_details.h
@@ -14,6 +14,9 @@ enum MetricType {
   METRIC_CPU_USAGE,
   METRIC_PRIVATE_MEMORY_USAGE,
   METRIC_SHARED_MEMORY_USAGE,
+  METRIC_STARTUP_TIME,
+  METRIC_TEST_STARTUP_TIME,
+  METRIC_SESSION_RESTORE_TIME,
   METRIC_NUMBER_OF_METRICS
 };
 
diff --git a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
index abbb4b6..acc5612 100644
--- a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
+++ b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
@@ -11,17 +11,25 @@
 #include "base/string_number_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/performance_monitor/constants.h"
-#include "chrome/browser/performance_monitor/database.h"
-#include "chrome/browser/performance_monitor/performance_monitor.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/unpacked_installer.h"
+#include "chrome/browser/performance_monitor/constants.h"
+#include "chrome/browser/performance_monitor/database.h"
+#include "chrome/browser/performance_monitor/performance_monitor.h"
+#include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/sessions/session_restore.h"
+#include "chrome/browser/sessions/session_service.h"
+#include "chrome/browser/sessions/session_service_test_helper.h"
+#include "chrome/browser/sessions/session_service_factory.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/browser_navigator.h"
 #include "chrome/browser/ui/browser_tabstrip.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_notification_types.h"
@@ -35,13 +43,20 @@
 #include "content/public/browser/notification_service.h"
 #include "content/public/common/page_transition_types.h"
 #include "content/public/test/browser_test_utils.h"
+#include "content/public/test/test_navigation_observer.h"
 #include "content/public/test/test_utils.h"
 
+#if defined(OS_MACOSX)
+#include "base/mac/scoped_nsautorelease_pool.h"
+#endif
+
 using extensions::Extension;
 using performance_monitor::Event;
 
 namespace {
 
+const base::TimeDelta kMaxStartupTime = base::TimeDelta::FromMinutes(3);
+
 // Helper struct to store the information of an extension; this is needed if the
 // pointer to the extension ever becomes invalid (e.g., if we uninstall the
 // extension).
@@ -305,6 +320,54 @@ class PerformanceMonitorUncleanExitBrowserTest
   std::string second_profile_name_;
 };
 
+class PerformanceMonitorSessionRestoreBrowserTest
+    : public PerformanceMonitorBrowserTest {
+ public:
+  virtual void SetUpOnMainThread() OVERRIDE {
+    SessionStartupPref pref(SessionStartupPref::LAST);
+    SessionStartupPref::SetStartupPref(browser()->profile(), pref);
+#if defined(OS_CHROMEOS) || defined (OS_MACOSX)
+    // Undo the effect of kBrowserAliveWithNoWindows in defaults.cc so that we
+    // can get these test to work without quitting.
+    SessionServiceTestHelper helper(
+        SessionServiceFactory::GetForProfile(browser()->profile()));
+    helper.SetForceBrowserNotAliveWithNoWindows(true);
+    helper.ReleaseService();
+#endif
+
+    PerformanceMonitorBrowserTest::SetUpOnMainThread();
+  }
+
+  Browser* QuitBrowserAndRestore(Browser* browser, int expected_tab_count) {
+    Profile* profile = browser->profile();
+
+    // Close the browser.
+    g_browser_process->AddRefModule();
+    content::WindowedNotificationObserver observer(
+        chrome::NOTIFICATION_BROWSER_CLOSED,
+        content::NotificationService::AllSources());
+    browser->window()->Close();
+#if defined(OS_MACOSX)
+    // BrowserWindowController depends on the auto release pool being recycled
+    // in the message loop to delete itself, which frees the Browser object
+    // which fires this event.
+    AutoreleasePool()->Recycle();
+#endif
+    observer.Wait();
+
+    // Create a new window, which should trigger session restore.
+    ui_test_utils::BrowserAddedObserver window_observer;
+    content::TestNavigationObserver navigation_observer(
+        content::NotificationService::AllSources(), NULL, expected_tab_count);
+    chrome::NewEmptyWindow(profile);
+    Browser* new_browser = window_observer.WaitForSingleNewBrowser();
+    navigation_observer.Wait();
+    g_browser_process->ReleaseModule();
+
+    return new_browser;
+  }
+};
+
 // Test that PerformanceMonitor will correctly record an extension installation
 // event.
 IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, InstallExtensionEvent) {
@@ -631,4 +694,29 @@ IN_PROC_BROWSER_TEST_F(PerformanceMonitorUncleanExitBrowserTest,
   ASSERT_EQ(second_profile_name_, event_profile);
 }
 
+IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, StartupTime) {
+  Database::MetricInfoVector metrics = GetStats(METRIC_TEST_STARTUP_TIME);
+
+  ASSERT_EQ(1u, metrics.size());
+  ASSERT_LT(metrics[0].value, kMaxStartupTime.ToInternalValue());
+}
+
+IN_PROC_BROWSER_TEST_F(PerformanceMonitorSessionRestoreBrowserTest,
+                       StartupWithSessionRestore) {
+  ui_test_utils::NavigateToURL(
+      browser(),
+      ui_test_utils::GetTestUrl(FilePath(FilePath::kCurrentDirectory),
+                                FilePath(FILE_PATH_LITERAL("title1.html"))));
+
+  QuitBrowserAndRestore(browser(), 1);
+
+  Database::MetricInfoVector metrics = GetStats(METRIC_TEST_STARTUP_TIME);
+  ASSERT_EQ(1u, metrics.size());
+  ASSERT_LT(metrics[0].value, kMaxStartupTime.ToInternalValue());
+
+  metrics = GetStats(METRIC_SESSION_RESTORE_TIME);
+  ASSERT_EQ(1u, metrics.size());
+  ASSERT_LT(metrics[0].value, kMaxStartupTime.ToInternalValue());
+}
+
 }  // namespace performance_monitor
diff --git a/chrome/browser/performance_monitor/startup_timer.cc b/chrome/browser/performance_monitor/startup_timer.cc
new file mode 100644
index 0000000..0af0a57
--- /dev/null
+++ b/chrome/browser/performance_monitor/startup_timer.cc
@@ -0,0 +1,137 @@
+// 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.
+
+#include "chrome/browser/performance_monitor/startup_timer.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/string_number_conversions.h"
+#include "chrome/browser/performance_monitor/database.h"
+#include "chrome/browser/performance_monitor/performance_monitor.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_source.h"
+#include "content/public/browser/notification_types.h"
+
+namespace performance_monitor {
+
+namespace {
+// Needed because Database::AddMetric is overloaded, so base::Bind doesn't work.
+void AddMetricToDatabaseOnBackgroundThread(Database* database,
+                                           MetricType metric,
+                                           std::string value) {
+  database->AddMetric(metric, value);
+}
+
+}  // namespace
+
+// static
+StartupTimer* StartupTimer::g_startup_timer_ = NULL;
+
+StartupTimer::StartupTimer() : startup_begin_(base::TimeTicks::Now()),
+                               startup_type_(STARTUP_NORMAL),
+                               performance_monitor_initialized_(false) {
+  CHECK(!g_startup_timer_);
+  g_startup_timer_ = this;
+
+  // We need this check because, under certain rare circumstances,
+  // NotificationService::current() will return null, and this will cause a
+  // segfault in NotificationServiceImpl::AddObserver(). Currently, this only
+  // happens as a result of the child process launched by BrowserMainTest.
+  // WarmConnectionFieldTrial_Invalid.
+  if (content::NotificationService::current()) {
+    registrar_.Add(this, chrome::NOTIFICATION_PERFORMANCE_MONITOR_INITIALIZED,
+                   content::NotificationService::AllSources());
+  }
+}
+
+StartupTimer::~StartupTimer() {
+  DCHECK(this == g_startup_timer_);
+  g_startup_timer_ = NULL;
+}
+
+bool StartupTimer::SignalStartupComplete(StartupType startup_type) {
+  DCHECK(elapsed_startup_time_ == base::TimeDelta());
+
+  startup_type_ = startup_type;
+
+  elapsed_startup_time_ =
+      base::TimeTicks::Now() - total_pause_ - startup_begin_;
+
+  if (performance_monitor_initialized_)
+    InsertElapsedStartupTime();
+
+  return true;
+}
+
+// static
+void StartupTimer::PauseTimer() {
+  // Check that the timer is not already paused.
+  DCHECK(g_startup_timer_->pause_started_ == base::TimeTicks());
+
+  g_startup_timer_->pause_started_ = base::TimeTicks::Now();
+}
+
+// static
+void StartupTimer::UnpauseTimer() {
+  // Check that the timer has been paused.
+  DCHECK(g_startup_timer_->pause_started_ != base::TimeTicks());
+
+  g_startup_timer_->total_pause_ += base::TimeTicks::Now() -
+                                    g_startup_timer_->pause_started_;
+
+  g_startup_timer_->pause_started_ = base::TimeTicks();
+}
+
+void StartupTimer::Observe(int type,
+                           const content::NotificationSource& source,
+                           const content::NotificationDetails& details) {
+  CHECK(type == chrome::NOTIFICATION_PERFORMANCE_MONITOR_INITIALIZED);
+  performance_monitor_initialized_ = true;
+  if (elapsed_startup_time_ != base::TimeDelta())
+    InsertElapsedStartupTime();
+  if (elapsed_session_restore_times_.size())
+    InsertElapsedSessionRestoreTime();
+}
+
+// static
+void StartupTimer::SetElapsedSessionRestoreTime(
+    const base::TimeDelta& elapsed_session_restore_time) {
+  g_startup_timer_->elapsed_session_restore_times_.push_back(
+      elapsed_session_restore_time);
+
+  if (g_startup_timer_->performance_monitor_initialized_)
+    g_startup_timer_->InsertElapsedSessionRestoreTime();
+}
+
+void StartupTimer::InsertElapsedStartupTime() {
+  content::BrowserThread::PostBlockingPoolSequencedTask(
+      Database::kDatabaseSequenceToken,
+      FROM_HERE,
+      base::Bind(
+          &AddMetricToDatabaseOnBackgroundThread,
+          base::Unretained(PerformanceMonitor::GetInstance()->database()),
+          startup_type_ == STARTUP_NORMAL ? METRIC_STARTUP_TIME
+                                          : METRIC_TEST_STARTUP_TIME,
+          base::Int64ToString(elapsed_startup_time_.ToInternalValue())));
+}
+
+void StartupTimer::InsertElapsedSessionRestoreTime() {
+  for (std::vector<base::TimeDelta>::const_iterator iter =
+           elapsed_session_restore_times_.begin();
+       iter != elapsed_session_restore_times_.end(); ++iter) {
+    content::BrowserThread::PostBlockingPoolSequencedTask(
+        Database::kDatabaseSequenceToken,
+        FROM_HERE,
+        base::Bind(
+            &AddMetricToDatabaseOnBackgroundThread,
+            base::Unretained(PerformanceMonitor::GetInstance()->database()),
+            METRIC_SESSION_RESTORE_TIME,
+            base::Int64ToString(iter->ToInternalValue())));
+  }
+}
+
+}  // namespace performance_monitor
diff --git a/chrome/browser/performance_monitor/startup_timer.h b/chrome/browser/performance_monitor/startup_timer.h
new file mode 100644
index 0000000..2bab4db
--- /dev/null
+++ b/chrome/browser/performance_monitor/startup_timer.h
@@ -0,0 +1,103 @@
+// 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_
diff --git a/chrome/browser/sessions/session_restore.cc b/chrome/browser/sessions/session_restore.cc
index 7351544..2906eec 100644
--- a/chrome/browser/sessions/session_restore.cc
+++ b/chrome/browser/sessions/session_restore.cc
@@ -20,6 +20,7 @@
 #include "base/stringprintf.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/performance_monitor/startup_timer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
@@ -440,6 +441,8 @@ void TabLoader::HandleTabClosedOrLoaded(NavigationController* tab) {
   if (tabs_loading_.empty() && tabs_to_load_.empty()) {
     base::TimeDelta time_to_load =
         base::TimeTicks::Now() - restore_started_;
+    performance_monitor::StartupTimer::SetElapsedSessionRestoreTime(
+        time_to_load);
     UMA_HISTOGRAM_CUSTOM_TIMES(
         "SessionRestore.AllTabsLoaded",
         time_to_load,
diff --git a/chrome/browser/sessions/session_restore_browsertest.cc b/chrome/browser/sessions/session_restore_browsertest.cc
index 154bf0a..9155f82 100644
--- a/chrome/browser/sessions/session_restore_browsertest.cc
+++ b/chrome/browser/sessions/session_restore_browsertest.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/sessions/session_restore.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
+#include "chrome/browser/sessions/session_service_test_helper.h"
 #include "chrome/browser/sessions/tab_restore_service.h"
 #include "chrome/browser/sessions/tab_restore_service_factory.h"
 #include "chrome/browser/ui/browser.h"
@@ -51,8 +52,10 @@ class SessionRestoreTest : public InProcessBrowserTest {
     if (strcmp(test_info->name(), "NoSessionRestoreNewWindowChromeOS")) {
       // Undo the effect of kBrowserAliveWithNoWindows in defaults.cc so that we
       // can get these test to work without quitting.
-      SessionServiceFactory::GetForProfile(browser()->profile())->
-          force_browser_not_alive_with_no_windows_ = true;
+      SessionServiceTestHelper helper(
+          SessionServiceFactory::GetForProfile(browser()->profile()));
+      helper.SetForceBrowserNotAliveWithNoWindows(true);
+      helper.ReleaseService();
     }
 #endif
   }
diff --git a/chrome/browser/sessions/session_service.h b/chrome/browser/sessions/session_service.h
index 97621cf..f40ad3a 100644
--- a/chrome/browser/sessions/session_service.h
+++ b/chrome/browser/sessions/session_service.h
@@ -52,7 +52,6 @@ class NavigationEntry;
 // of the browser.
 class SessionService : public BaseSessionService,
                        public content::NotificationObserver {
-  friend class SessionRestoreTest;
   friend class SessionServiceTestHelper;
  public:
   // Used to distinguish an application window from a normal one.
diff --git a/chrome/browser/sessions/session_service_test_helper.cc b/chrome/browser/sessions/session_service_test_helper.cc
index 2953e02..3f02a4c 100644
--- a/chrome/browser/sessions/session_service_test_helper.cc
+++ b/chrome/browser/sessions/session_service_test_helper.cc
@@ -50,6 +50,12 @@ void SessionServiceTestHelper::SetTabUserAgentOverride(
   service()->SetTabUserAgentOverride(window_id, tab_id, user_agent_override);
 }
 
+void SessionServiceTestHelper::SetForceBrowserNotAliveWithNoWindows(
+    bool force_browser_not_alive_with_no_windows) {
+  service()->force_browser_not_alive_with_no_windows_ =
+      force_browser_not_alive_with_no_windows;
+}
+
 // Be sure and null out service to force closing the file.
 void SessionServiceTestHelper::ReadWindows(
     std::vector<SessionWindow*>* windows) {
diff --git a/chrome/browser/sessions/session_service_test_helper.h b/chrome/browser/sessions/session_service_test_helper.h
index 3419712..cccb1d3 100644
--- a/chrome/browser/sessions/session_service_test_helper.h
+++ b/chrome/browser/sessions/session_service_test_helper.h
@@ -43,6 +43,9 @@ class SessionServiceTestHelper {
                                const SessionID& tab_id,
                                const std::string& user_agent_override);
 
+  void SetForceBrowserNotAliveWithNoWindows(
+      bool force_browser_not_alive_with_no_windows);
+
   // Reads the contents of the last session.
   void ReadWindows(std::vector<SessionWindow*>* windows);
 
diff --git a/chrome/browser/ui/startup/startup_browser_creator_impl.cc b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
index adcb2f3..4bb4994 100644
--- a/chrome/browser/ui/startup/startup_browser_creator_impl.cc
+++ b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
@@ -29,6 +29,7 @@
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
+#include "chrome/browser/performance_monitor/startup_timer.h"
 #include "chrome/browser/prefs/incognito_mode_prefs.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
@@ -606,8 +607,8 @@ bool StartupBrowserCreatorImpl::ProcessStartupURLs(
       return false;
     }
 
-  uint32 restore_behavior = SessionRestore::SYNCHRONOUS |
-                            SessionRestore::ALWAYS_CREATE_TABBED_BROWSER;
+    uint32 restore_behavior = SessionRestore::SYNCHRONOUS |
+                              SessionRestore::ALWAYS_CREATE_TABBED_BROWSER;
 #if defined(OS_MACOSX)
     // On Mac, when restoring a session with no windows, suppress the creation
     // of a new window in the case where the system is launching Chrome via a
@@ -618,10 +619,18 @@ bool StartupBrowserCreatorImpl::ProcessStartupURLs(
     }
 #endif
 
+    // Pause the StartupTimer. Since the restore here is synchronous, we can
+    // keep these two metrics (browser startup time and session restore time)
+    // separate.
+    performance_monitor::StartupTimer::PauseTimer();
+
     Browser* browser = SessionRestore::RestoreSession(profile_,
                                                       NULL,
                                                       restore_behavior,
                                                       urls_to_open);
+
+    performance_monitor::StartupTimer::UnpauseTimer();
+
     AddInfoBarsIfNecessary(browser, chrome::startup::IS_PROCESS_STARTUP);
     return true;
   }
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 69a83a2..312608a 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1648,6 +1648,8 @@
         'browser/performance_monitor/performance_monitor.h',
         'browser/performance_monitor/performance_monitor_util.cc',
         'browser/performance_monitor/performance_monitor_util.h',
+        'browser/performance_monitor/startup_timer.cc',
+        'browser/performance_monitor/startup_timer.h',
         'browser/platform_util.h',
         'browser/platform_util_android.cc',
         'browser/platform_util_aura.cc',