[ChromeDriver] Include both localhost addresses

For connections to localhost, ChromeDriver should test both IPv4 and
IPv6 formats to resolve issue where DevTools may not be listening on the
expected protocol.

Bug: chromedriver:3316, b/147285732
Change-Id: Iecbf8f4f1c8df6138fd8ef8d908217e760e13923
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2013892Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Tricia Crichton <triciac@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734228}

chrome/test/chromedriver/net/websocket.cc

@@ -98,8 +98,16 @@ void WebSocket::Connect(net::CompletionOnceCallback callback) {
     VLOG(0) << "resolved " << url_.HostNoBracketsPiece() << " to " << json;
   }
 
+  if (url_.host() == "localhost") {
+    // ensure that both localhost addresses are included
+    // see https://bugs.chromium.org/p/chromedriver/issues/detail?id=3316
+    addresses.push_back(net::IPEndPoint(net::IPAddress::IPv4Localhost(), port));
+    addresses.push_back(net::IPEndPoint(net::IPAddress::IPv6Localhost(), port));
+    addresses.Deduplicate();
+  }
+
   net::NetLogSource source;
-  socket_.reset(new net::TCPClientSocket(addresses, NULL, NULL, source));
+  socket_.reset(new net::TCPClientSocket(addresses, nullptr, nullptr, source));
 
   state_ = CONNECTING;
   connect_callback_ = std::move(callback);