Increase warning level to 4 on Visual Studio

chrome/test/selenium/selenium_test.cc

 // Copyright (c) 2011 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.
 
 // This is a gTest-based test that runs the Selenium Core testsuite in Chrome
 // using the UITest automation.  The number of total and failed tests are
 // written to stdout.
 //
 // TODO(darin): output the names of the failed tests so we can easily track
 // deviations from the expected output.
@@ skipping 100 matching lines @@
     scoped_refptr<TabProxy> tab(GetActiveTab());
     tab->NavigateToURL(test_url);
 
     // Wait for the test to finish.
     ASSERT_TRUE(WaitUntilCookieValue(
         tab.get(), test_url, "__tests_finished",
         TestTimeouts::huge_test_timeout_ms(), "1"));
 
     std::string cookie;
     ASSERT_TRUE(tab->GetCookieByName(test_url, "__num_tests_total", &cookie));
-    total->swap(UTF8ToWide(cookie));
+    *total = UTF8ToWide(cookie);
     ASSERT_FALSE(total->empty());
     ASSERT_TRUE(tab->GetCookieByName(test_url, "__tests_failed", &cookie));
-    failed->swap(UTF8ToWide(cookie));
+    *failed = UTF8ToWide(cookie);
     // The __tests_failed cookie will be empty if all the tests pass.
 #endif
   }
 
   void RunTest(ResultsList* new_passes_list, ResultsList* new_failures_list) {
     std::string expected_failures;
     bool have_expected_results = ReadExpectedResults(&expected_failures);
     ASSERT_TRUE(have_expected_results);
 
     std::wstring total, failed;
@@ skipping 35 matching lines @@
   }
 
   if (!new_passes_list.empty()) {
     printf("new tests passing:\n");
     ResultsList::const_iterator it = new_passes_list.begin();
     for (; it != new_passes_list.end(); ++it)
       printf("  %s\n", it->c_str());
     printf("\n");
   }
 }