[cros] Fake a stub user login when no --login-manager and --login-user are given.

chrome/browser/chromeos/login/existing_user_controller_browsertest.cc

Index: chrome/browser/chromeos/login/existing_user_controller_browsertest.cc
diff --git a/chrome/browser/chromeos/login/existing_user_controller_browsertest.cc b/chrome/browser/chromeos/login/existing_user_controller_browsertest.cc
index fcbfada5b657222f3451deb8fc808897479bcb33..8164711468107d35231a1616dc2efe0079440bd6 100644
--- a/chrome/browser/chromeos/login/existing_user_controller_browsertest.cc
+++ b/chrome/browser/chromeos/login/existing_user_controller_browsertest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chromeos/cros/cros_in_process_browser_test.h"
@@ -21,6 +22,7 @@
 #include "chrome/browser/chromeos/login/mock_url_fetchers.h"
 #include "chrome/browser/chromeos/login/mock_user_manager.h"
 #include "chrome/browser/chromeos/login/wizard_controller.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/net/gaia/mock_url_fetcher_factory.h"
 #include "chrome/test/base/testing_profile.h"
 #include "chrome/test/base/ui_test_utils.h"
@@ -170,6 +172,10 @@ class ExistingUserControllerTest : public CrosInProcessBrowserTest {
         .Times(1);
   }
 
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
+    command_line->AppendSwitch(switches::kLoginManager);

[Nikita (slow), 2012/06/20 13:28:32]

Please use NiceMock as discussed to cleanup output.
I expect that adding --login-manager here might pollute output even more.

[Ivan Korotkov, 2012/06/21 12:25:12]

Done.

+  }
+
   virtual void SetUpOnMainThread() OVERRIDE {
     testing_profile_.reset(new TestingProfile());
     existing_user_controller_.reset(