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

chrome/browser/automation/testing_automation_provider.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 <map>
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 2281 matching lines @@
 
 #if defined(OS_CHROMEOS)
   handler_map["GetLoginInfo"] = &TestingAutomationProvider::GetLoginInfo;
   handler_map["ShowCreateAccountUI"] =
       &TestingAutomationProvider::ShowCreateAccountUI;
   handler_map["ExecuteJavascriptInOOBEWebUI"] =
       &TestingAutomationProvider::ExecuteJavascriptInOOBEWebUI;
   handler_map["LoginAsGuest"] = &TestingAutomationProvider::LoginAsGuest;
   handler_map["AddLoginEventObserver"] =
       &TestingAutomationProvider::AddLoginEventObserver;
+  handler_map["SignOut"] = &TestingAutomationProvider::SignOut;
 
   handler_map["LockScreen"] = &TestingAutomationProvider::LockScreen;
   handler_map["UnlockScreen"] = &TestingAutomationProvider::UnlockScreen;
   handler_map["SignoutInScreenLocker"] =
       &TestingAutomationProvider::SignoutInScreenLocker;
 
   handler_map["GetBatteryInfo"] = &TestingAutomationProvider::GetBatteryInfo;
 
   handler_map["GetNetworkInfo"] = &TestingAutomationProvider::GetNetworkInfo;
   handler_map["NetworkScan"] = &TestingAutomationProvider::NetworkScan;
@@ skipping 4847 matching lines @@
       *browser_handle = browser_tracker_->Add(browser);
       *success = true;
     }
   }
 }
 
 void TestingAutomationProvider::OnRemoveProvider() {
   if (g_browser_process)
     g_browser_process->GetAutomationProviderList()->RemoveProvider(this);
 }