Make the simple QUIC client able to resolve hosts.

net/tools/quic/quic_client_bin.cc

Index: net/tools/quic/quic_client_bin.cc
diff --git a/net/tools/quic/quic_client_bin.cc b/net/tools/quic/quic_client_bin.cc
index 259111f8782dd6e2e94c74c3c35d5238c24fe0cb..752ccd8cd9ac49b5b7d67fe9056b03b62b3f5888 100644
--- a/net/tools/quic/quic_client_bin.cc
+++ b/net/tools/quic/quic_client_bin.cc
@@ -47,6 +47,8 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "net/base/ip_endpoint.h"
+#include "net/base/net_errors.h"
+#include "net/base/net_log.h"
 #include "net/base/privacy_mode.h"
 #include "net/cert/cert_verifier.h"
 #include "net/http/transport_security_state.h"
@@ -57,6 +59,7 @@
 #include "net/tools/epoll_server/epoll_server.h"
 #include "net/tools/quic/quic_client.h"
 #include "net/tools/quic/spdy_utils.h"
+#include "net/tools/quic/synchronous_host_resolver.h"
 #include "url/gurl.h"
 
 using base::StringPiece;
@@ -169,14 +172,18 @@ int main(int argc, char *argv[]) {
   // protocol is required in the URL.
   GURL url(urls[0]);
   string host = FLAGS_host;
-  // TODO(rtenneti): get ip_addr from hostname by doing host resolution.
   if (host.empty()) {
-    LOG(ERROR) << "--host must be specified\n";
-    return 1;
+    host = url.host();
   }
   if (!net::ParseIPLiteralToNumber(host, &ip_addr)) {
-    LOG(ERROR) << "--host could not be parsed as an IP address\n";
-    return 1;
+    net::AddressList addresses;
+    int rv = net::tools::SynchronousHostResolver::Resolve(host, &addresses);
+    if (rv != net::OK) {
+      LOG(ERROR) << "Unable to resolve '" << host << "' : "
+                 << net::ErrorToString(rv);
+      return 1;
+    }
+    ip_addr = addresses[0].address();
   }
 
   string host_port = net::IPAddressToStringWithPort(ip_addr, FLAGS_port);