[chromeos] Fix Logout automation when no browser windows are present.

chrome/browser/automation/testing_automation_provider_chromeos.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/automation/testing_automation_provider.h"
 
+#include "ash/shell.h"
+#include "ash/system/tray/system_tray_delegate.h"
 #include "base/command_line.h"
 #include "base/i18n/time_formatting.h"
 #include "base/stringprintf.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/automation/automation_provider_json.h"
 #include "chrome/browser/automation/automation_provider_observers.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_util.h"
 #include "chrome/browser/chromeos/audio/audio_handler.h"
@@ skipping 274 matching lines @@
   int observer_id = automation_event_queue_->AddObserver(
       new LoginEventObserver(automation_event_queue_.get(),
                              controller));
 
   // Return the observer's id.
   DictionaryValue return_value;
   return_value.SetInteger("observer_id", observer_id);
   reply.SendSuccess(&return_value);
 }
 
+void TestingAutomationProvider::SignOut(DictionaryValue* args,
+                                        IPC::Message* reply_message) {
+  ash::Shell::GetInstance()->tray_delegate()->SignOut();
+  // Sign out has the side effect of restarting the session_manager
+  // and chrome, thereby severing the automation channel, so it's
+  // not really necessary to send a reply back. The next line is
+  // for consistency with other methods.
+  AutomationJSONReply(this, reply_message).SendSuccess(NULL);
+}
+
 void TestingAutomationProvider::LockScreen(DictionaryValue* args,
                                            IPC::Message* reply_message) {
   new ScreenLockUnlockObserver(this, reply_message, true);
   DBusThreadManager::Get()->GetPowerManagerClient()->
       NotifyScreenLockRequested();
 }
 
 void TestingAutomationProvider::UnlockScreen(DictionaryValue* args,
                                              IPC::Message* reply_message) {
   std::string password;
@@ skipping 924 matching lines @@
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       AddObserver(power_manager_observer_);
 }
 
 void TestingAutomationProvider::RemoveChromeosObservers() {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       RemoveObserver(power_manager_observer_);
   delete power_manager_observer_;
   power_manager_observer_ = NULL;
 }