Restart Chrome on ChromeOS as early as possible to speed up restart.

chrome/browser/chromeos/login/login_utils.cc

Index: chrome/browser/chromeos/login/login_utils.cc
diff --git a/chrome/browser/chromeos/login/login_utils.cc b/chrome/browser/chromeos/login/login_utils.cc
index caef5731dcf6872eacfe81bacaf3bde15eead31c..9a591e4da2ac7c47957f5ca822190c9da5a4e1aa 100644
--- a/chrome/browser/chromeos/login/login_utils.cc
+++ b/chrome/browser/chromeos/login/login_utils.cc
@@ -144,6 +144,7 @@ class LoginUtilsImpl
       LoginStatusConsumer* consumer) OVERRIDE;
   virtual void RestoreAuthenticationSession(Profile* profile) OVERRIDE;
   virtual void InitRlzDelayed(Profile* user_profile) OVERRIDE;
+  virtual bool RestartToApplyPerSessionFlagsIfNeed(Profile* profile) OVERRIDE;
 
   // OAuth2LoginManager::Observer overrides.
   virtual void OnSessionRestoreStateChanged(
@@ -220,6 +221,12 @@ class LoginUtilsImpl
   // not happen while we are still fetching new OAuth refresh tokens.
   void AttemptRestart(Profile* profile);
 
+  // Returns new CommandLine with per-user flags.
+  CommandLine CreatePerSessionCommandLine(Profile* profile);
+
+  // Returns true if restart is needed to apply per-session flags.
+  bool NeedRestartToApplyPerSessionFlags(const CommandLine& user_flags);
+
   UserContext user_context_;
 
   // True if the authentication profile's cookie jar should contain
@@ -311,25 +318,8 @@ void LoginUtilsImpl::DoBrowserLaunchOnLocaleLoadedImpl(
     return;
   }
 
-  CommandLine user_flags(CommandLine::NO_PROGRAM);
-  about_flags::PrefServiceFlagsStorage flags_storage_(profile->GetPrefs());
-  about_flags::ConvertFlagsToSwitches(&flags_storage_, &user_flags,
-                                      about_flags::kAddSentinels);
-  // Only restart if needed and if not going into managed mode.
-  // Don't restart browser if it is not first profile in session.
-  if (UserManager::Get()->GetLoggedInUsers().size() == 1 &&
-      !UserManager::Get()->IsLoggedInAsLocallyManagedUser() &&
-      !about_flags::AreSwitchesIdenticalToCurrentCommandLine(
-          user_flags, *CommandLine::ForCurrentProcess())) {
-    CommandLine::StringVector flags;
-    // argv[0] is the program name |CommandLine::NO_PROGRAM|.
-    flags.assign(user_flags.argv().begin() + 1, user_flags.argv().end());
-    VLOG(1) << "Restarting to apply per-session flags...";
-    DBusThreadManager::Get()->GetSessionManagerClient()->SetFlagsForUser(
-        UserManager::Get()->GetActiveUser()->email(), flags);
-    AttemptRestart(profile);
+  if (RestartToApplyPerSessionFlagsIfNeed(profile))
     return;
-  }
 
   if (login_host) {
     login_host->SetStatusAreaVisible(true);
@@ -339,6 +329,7 @@ void LoginUtilsImpl::DoBrowserLaunchOnLocaleLoadedImpl(
   BootTimesLoader::Get()->AddLoginTimeMarker("BrowserLaunched", false);
 
   VLOG(1) << "Launching browser...";
+  TRACE_EVENT0("login", "LaunchBrowser");
   StartupBrowserCreator browser_creator;
   int return_code;
   chrome::startup::IsFirstRun first_run = first_run::IsChromeFirstRun() ?
@@ -685,6 +676,21 @@ void LoginUtilsImpl::InitRlzDelayed(Profile* user_profile) {
 #endif
 }
 
+bool LoginUtilsImpl::RestartToApplyPerSessionFlagsIfNeed(Profile* profile) {

[Nikita (slow), 2014/06/10 14:21:00]

nit: Move this to unnamed namespace.

[Alexander Alekseev, 2014/06/10 22:05:13]

It's called from profile_impl.cc .

I've moved it to a separate function in chromeos namespace.
But it is tricky, see other comment.

[Nikita (slow), 2014/06/11 12:42:51]

Sorry, since this one is called from ProfileImpl you should not make it a global
function instead which is not advised per Chromium style guide.

You should move only those function that are called from this class only.

[Alexander Alekseev, 2014/06/11 15:15:50]

Done.

+  const CommandLine user_flags(CreatePerSessionCommandLine(profile));
+  if (!NeedRestartToApplyPerSessionFlags(user_flags))
+    return false;
+
+  CommandLine::StringVector flags;
+  // argv[0] is the program name |CommandLine::NO_PROGRAM|.
+  flags.assign(user_flags.argv().begin() + 1, user_flags.argv().end());
+  VLOG(1) << "Restarting to apply per-session flags...";
+  DBusThreadManager::Get()->GetSessionManagerClient()->SetFlagsForUser(
+      UserManager::Get()->GetActiveUser()->email(), flags);
+  AttemptRestart(profile);
+  return true;
+}
+
 void LoginUtilsImpl::InitRlz(Profile* user_profile, bool disabled) {
 #if defined(ENABLE_RLZ)
   PrefService* local_state = g_browser_process->local_state();
@@ -923,6 +929,32 @@ void LoginUtilsImpl::AttemptRestart(Profile* profile) {
   exit_after_session_restore_ = true;
 }
 
+CommandLine LoginUtilsImpl::CreatePerSessionCommandLine(Profile* profile) {

[Nikita (slow), 2014/06/10 14:21:00]

nit: Please move to unnamed namespace.

+  CommandLine user_flags(CommandLine::NO_PROGRAM);
+  about_flags::PrefServiceFlagsStorage flags_storage_(profile->GetPrefs());
+  about_flags::ConvertFlagsToSwitches(
+      &flags_storage_, &user_flags, about_flags::kAddSentinels);
+  return user_flags;
+}
+
+bool LoginUtilsImpl::NeedRestartToApplyPerSessionFlags(

[Nikita (slow), 2014/06/10 14:21:00]

nit: Same here.

+    const CommandLine& user_flags) {
+  // Don't restart browser if it is not first profile in session.
+  if (UserManager::Get()->GetLoggedInUsers().size() != 1)
+    return false;
+
+  // Only restart if needed and if not going into managed mode.
+  if (UserManager::Get()->IsLoggedInAsLocallyManagedUser())
+    return false;
+
+  if (about_flags::AreSwitchesIdenticalToCurrentCommandLine(

[Nikita (slow), 2014/06/10 14:21:00]

nit: rewrite this as 

return !about_flags::AreSwitchesIdenticalToCurrentCommandLine(...);

+          user_flags, *CommandLine::ForCurrentProcess())) {
+    return false;
+  }
+
+  return true;
+}
+
 // static
 void LoginUtils::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterBooleanPref(prefs::kFactoryResetRequested, false);