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/logging.h"
@@ skipping 106 matching lines @@
 #if defined(OS_CHROMEOS)
   chromeos::BootTimesLoader::Get()->AddLogoutTimeMarker(
       "StartedClosingWindows", false);
 #endif
   scoped_refptr<BrowserCloseManager> browser_close_manager =
       new BrowserCloseManager;
   browser_close_manager->StartClosingBrowsers();
 }
 
 void AttemptUserExit() {
+  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);

[DaveMoore, 2013/08/30 22:51:15]

Be sure to turn off tracing if the attempt to exit fails.

[Mr4D (OOO till 08-26), 2013/08/31 02:03:44]

Good one. I haven't figured out yet how it can fail. Added a todo and will
address that later.
Note: This is a debug flag and even if the user would cancel, the buffer
capturing would stop once the buffer is full and the next time we would come
here it would start again.

Nevertheless - will ask sky about all possibilities of all OS'es since they can
vary here.

+  }
+  TRACE_EVENT0("shutdown", "AttemptUserExit");

[DaveMoore, 2013/08/30 22:51:15]

It sure would be good to get system tracing on ChromeOS too. This complicates
things quite a bit though, so it probably should come on a subsequent cl.

[Mr4D (OOO till 08-26), 2013/08/31 02:03:44]

We can add "system events" also - in a later CL as suggested.

+
 #if defined(OS_CHROMEOS)
   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);
@@ skipping 227 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