Adding shutdown tracing capabilities

chrome/browser/lifetime/application_lifetime.cc

 // 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/lifetime/application_lifetime.h"
 
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/prefs/pref_service.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/download/download_service.h"
@@ skipping 98 matching lines @@
   chromeos::BootTimesLoader::Get()->AddLogoutTimeMarker(
       "StartedClosingWindows", false);
 #endif
   scoped_refptr<BrowserCloseManager> browser_close_manager =
       new BrowserCloseManager;
   browser_close_manager->StartClosingBrowsers();
 }
 
 void AttemptUserExit() {
 #if defined(OS_CHROMEOS)
+  StartShutdownTracing();
   chromeos::BootTimesLoader::Get()->AddLogoutTimeMarker("LogoutStarted", false);
   // Write /tmp/uptime-logout-started as well.
   const char kLogoutStarted[] = "logout-started";
   chromeos::BootTimesLoader::Get()->RecordCurrentStats(kLogoutStarted);
 
   // Login screen should show up in owner's locale.
   PrefService* state = g_browser_process->local_state();
   if (state) {
     std::string owner_locale = state->GetString(prefs::kOwnerLocale);
     if (!owner_locale.empty() &&
         state->GetString(prefs::kApplicationLocale) != owner_locale &&
         !state->IsManagedPreference(prefs::kApplicationLocale)) {
       state->SetString(prefs::kApplicationLocale, owner_locale);
+      TRACE_EVENT0("shutdown", "CommitPendingWrite");
       state->CommitPendingWrite();
     }
   }
   g_session_manager_requested_shutdown = false;
   // On ChromeOS, always terminate the browser, regardless of the result of
   // AreAllBrowsersCloseable(). See crbug.com/123107.
   chrome::NotifyAndTerminate(true);
 #else
   // Reset the restart bit that might have been set in cancelled restart
   // request.
   PrefService* pref_service = g_browser_process->local_state();
   pref_service->SetBoolean(prefs::kRestartLastSessionOnShutdown, false);
   AttemptExitInternal();
 #endif
 }
 
+void StartShutdownTracing() {

[James Cook, 2013/09/03 21:23:36]

optional nit: MaybeStartShutdownTracing()?

[Mr4D (OOO till 08-26), 2013/09/03 22:18:58]

For what Chrome is concerned the tracing gets started after this call. The only
reason why it does not get started is that the user didn't want it or later on
someone cannot write the log.

Adding a "Maybe" here would require a "Maybe" in a lot of other places. As such
I don't do it. :)

+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kTraceShutdown)) {
+    base::debug::CategoryFilter category_filter(
+        command_line.GetSwitchValueASCII(switches::kTraceShutdown));
+    base::debug::TraceLog::GetInstance()->SetEnabled(
+        category_filter,
+        base::debug::TraceLog::RECORD_UNTIL_FULL);
+  }
+  TRACE_EVENT0("shutdown", "AttemptUserExit");

[James Cook, 2013/09/03 21:23:36]

Are you sure you want to do this here, since sometimes this is called from
OnShutdownStarting?

[Mr4D (OOO till 08-26), 2013/09/03 22:18:58]

Indeed - Done.

+}
+
 // The Android implementation is in application_lifetime_android.cc
 #if !defined(OS_ANDROID)
 void AttemptRestart() {
   // TODO(beng): Can this use ProfileManager::GetLoadedProfiles instead?
   for (chrome::BrowserIterator it; !it.done(); it.Next())
     content::BrowserContext::SaveSessionState(it->profile());
 
   PrefService* pref_service = g_browser_process->local_state();
   pref_service->SetBoolean(prefs::kWasRestarted, true);
 
@@ skipping 197 matching lines @@
   //    environment is still active.
   if (browser->host_desktop_type() == chrome::HOST_DESKTOP_TYPE_NATIVE)
     return !ash::Shell::HasInstance();
   else if (browser->host_desktop_type() == chrome::HOST_DESKTOP_TYPE_ASH)
     return BrowserList::GetInstance(chrome::HOST_DESKTOP_TYPE_NATIVE)->empty();
 #endif
   return true;
 }
 
 }  // namespace chrome