[ChromeDriver] Listen on both IPv4 & IPv6

On hosts that support both IPv4 and IPv6, ChromeDriver now listens on
both protocols.

Bug: chromedriver:779
Change-Id: I4a115cc0ca5cf0396acdad8d4c1a72f169120368
Reviewed-on: https://chromium-review.googlesource.com/1080448Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Reviewed-by: Jonathon Kereliuk <kereliuk@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564984}

chrome/test/chromedriver/server/chromedriver_server.cc

@@ -77,22 +77,20 @@ class HttpServer : public net::HttpServer::Delegate {
 
   ~HttpServer() override {}
 
-  bool Start(uint16_t port, bool allow_remote) {
+  int Start(uint16_t port, bool allow_remote, bool use_ipv4) {
     std::unique_ptr<net::ServerSocket> server_socket(
         new net::TCPServerSocket(NULL, net::NetLogSource()));
-    if (ListenOnIPv4(server_socket.get(), port, allow_remote) != net::OK) {
-      // This will work on an IPv6-only host, but we will be IPv4-only on
-      // dual-stack hosts.
-      // TODO(samuong): change this to listen on both IPv4 and IPv6.
-      VLOG(0) << "listen on IPv4 failed, trying IPv6";
-      if (ListenOnIPv6(server_socket.get(), port, allow_remote) != net::OK) {
-        VLOG(1) << "listen on both IPv4 and IPv6 failed, giving up";
-        return false;
-      }
+    int status = use_ipv4
+                     ? ListenOnIPv4(server_socket.get(), port, allow_remote)
+                     : ListenOnIPv6(server_socket.get(), port, allow_remote);
+    if (status != net::OK) {
+      VLOG(0) << "listen on " << (use_ipv4 ? "IPv4" : "IPv6")
+              << " failed with error " << net::ErrorToShortString(status);
+      return status;
     }
     server_.reset(new net::HttpServer(std::move(server_socket), this));
     net::IPEndPoint address;
-    return server_->GetLocalAddress(&address) == net::OK;
+    return server_->GetLocalAddress(&address);
   }
 
   // Overridden from net::HttpServer::Delegate:
@@ -174,24 +172,48 @@ void HandleRequestOnIOThread(
 }
 
 base::LazyInstance<base::ThreadLocalPointer<HttpServer>>::DestructorAtExit
-    lazy_tls_server = LAZY_INSTANCE_INITIALIZER;
+    lazy_tls_server_ipv4 = LAZY_INSTANCE_INITIALIZER;
+base::LazyInstance<base::ThreadLocalPointer<HttpServer>>::DestructorAtExit
+    lazy_tls_server_ipv6 = LAZY_INSTANCE_INITIALIZER;
 
 void StopServerOnIOThread() {
   // Note, |server| may be NULL.
-  HttpServer* server = lazy_tls_server.Pointer()->Get();
-  lazy_tls_server.Pointer()->Set(NULL);
+  HttpServer* server = lazy_tls_server_ipv4.Pointer()->Get();
+  lazy_tls_server_ipv4.Pointer()->Set(NULL);
+  delete server;
+
+  server = lazy_tls_server_ipv6.Pointer()->Get();
+  lazy_tls_server_ipv6.Pointer()->Set(NULL);
   delete server;
 }
 
 void StartServerOnIOThread(uint16_t port,
                            bool allow_remote,
                            const HttpRequestHandlerFunc& handle_request_func) {
-  std::unique_ptr<HttpServer> temp_server(new HttpServer(handle_request_func));
-  if (!temp_server->Start(port, allow_remote)) {
-    printf("Port not available. Exiting...\n");
+  std::unique_ptr<HttpServer> temp_server;
+
+  temp_server.reset(new HttpServer(handle_request_func));
+  int ipv4_status = temp_server->Start(port, allow_remote, true);
+  if (ipv4_status == net::OK) {
+    lazy_tls_server_ipv4.Pointer()->Set(temp_server.release());
+  } else if (ipv4_status == net::ERR_ADDRESS_IN_USE) {
+    printf("IPv4 port not available. Exiting...\n");
+    exit(1);
+  }
+
+  temp_server.reset(new HttpServer(handle_request_func));
+  int ipv6_status = temp_server->Start(port, allow_remote, false);
+  if (ipv6_status == net::OK) {
+    lazy_tls_server_ipv6.Pointer()->Set(temp_server.release());
+  } else if (ipv6_status == net::ERR_ADDRESS_IN_USE) {
+    printf("IPv6 port not available. Exiting...\n");
+    exit(1);
+  }
+
+  if (ipv4_status != net::OK && ipv6_status != net::OK) {
+    printf("Unable to start server with either IPv4 or IPv6. Exiting...\n");
     exit(1);
   }
-  lazy_tls_server.Pointer()->Set(temp_server.release());
 }
 
 void RunServer(uint16_t port,