Remove --enable-ipv6 and --disable-ipv6 command line flags.

chrome/browser/safe_browsing/safe_browsing_test.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.
 //
 // This test uses the safebrowsing test server published at
 // http://code.google.com/p/google-safe-browsing/ to test the safebrowsing
 // protocol implemetation. Details of the safebrowsing testing flow is
 // documented at
 // http://code.google.com/p/google-safe-browsing/wiki/ProtocolTesting
 //
@@ skipping 277 matching lines @@
     InProcessBrowserTest::SetUp();
   }
 
   void TearDown() override {
     InProcessBrowserTest::TearDown();
 
     SafeBrowsingService::RegisterFactory(NULL);
   }
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
-    // This test uses loopback. No need to use IPv6 especially it makes
-    // local requests slow on Windows trybot when ipv6 local address [::1]
-    // is not setup.
-    command_line->AppendSwitch(switches::kDisableIPv6);
-
     // TODO(lzheng): The test server does not understand download related
     // requests. We need to fix the server.
     command_line->AppendSwitch(switches::kSbDisableDownloadProtection);
 
     // TODO(gcasto): Generate new testing data that includes the
     // client-side phishing whitelist.
     command_line->AppendSwitch(
         switches::kDisableClientSidePhishingDetection);
 
     // TODO(kalman): Generate new testing data that includes the extension
@@ skipping 269 matching lines @@
               safe_browsing_helper->FetchDBToVerify(test_server(), step));
     EXPECT_GT(safe_browsing_helper->response_data().size(), 0U);
     last_step = step;
   }
 
   // Verifies with server if test is done and waits till server responses.
   EXPECT_EQ(net::URLRequestStatus::SUCCESS,
             safe_browsing_helper->VerifyTestComplete(test_server(), last_step));
   EXPECT_EQ("yes", safe_browsing_helper->response_data());
 }