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

chrome/browser/safe_browsing/safe_browsing_test.cc

Index: chrome/browser/safe_browsing/safe_browsing_test.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_test.cc b/chrome/browser/safe_browsing/safe_browsing_test.cc
index 0e1b7ae9786722f23728275cfe3ae2c1a08b62a5..04bebdd4e3638af4686296c4663f57aeb6823a17 100644
--- a/chrome/browser/safe_browsing/safe_browsing_test.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_test.cc
@@ -295,11 +295,6 @@ class SafeBrowsingServerTest : public InProcessBrowserTest {
   }
 
   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);