Make SecondLaunch UI test not-flaky by using more reliable

chrome/app/chrome_main_uitest.cc

 // Copyright (c) 2006-2008 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/test/ui/ui_test.h"
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "net/base/net_util.h"
@@ skipping 17 matching lines @@
 // Make sure that the testing interface is there and giving reasonable answers.
 TEST_F(ChromeMainTest, AppTestingInterface) {
   int window_count = 0;
   EXPECT_TRUE(automation()->GetBrowserWindowCount(&window_count));
   EXPECT_EQ(1, window_count);
 
   EXPECT_EQ(1, GetTabCount());
 }
 
 // Make sure that the second invocation creates a new window.
-// This test is disabled. See bug 5671.
-TEST_F(ChromeMainTest, DISABLED_SecondLaunch) {
+TEST_F(ChromeMainTest, SecondLaunch) {
   include_testing_id_ = false;
   use_existing_browser_ = true;
 
   LaunchBrowser(CommandLine(L""), false);
 
-  int window_count;
-  ASSERT_TRUE(automation()->WaitForWindowCountToChange(1, &window_count,
-                                                       action_timeout_ms()));
-  ASSERT_EQ(2, window_count);
+  ASSERT_TRUE(automation()->WaitForWindowCountToBecome(2, action_timeout_ms()));
 }
 
 TEST_F(ChromeMainTest, ReuseBrowserInstanceWhenOpeningFile) {
   include_testing_id_ = false;
   use_existing_browser_ = true;
 
   std::wstring test_file = test_data_directory_;
   file_util::AppendToPath(&test_file, L"empty.html");
 
   CommandLine command_line(L"");
   command_line.AppendLooseValue(test_file);
 
   LaunchBrowser(command_line, false);
 
   FilePath test_file_path(FilePath::FromWStringHack(test_file));
 
   ASSERT_TRUE(automation()->WaitForURLDisplayed(
       net::FilePathToFileURL(test_file_path), action_timeout_ms()));
 }