Implement WebPrescientNetworking::prefetchDNS.

chrome/renderer/net/prescient_networking_dispatcher.cc

Index: chrome/renderer/net/prescient_networking_dispatcher.cc
diff --git a/chrome/renderer/net/prescient_networking_dispatcher.cc b/chrome/renderer/net/prescient_networking_dispatcher.cc
index e97c167e39d2301a6e52c016912eda82c3b9a9d2..69d9bb1cc601409aa96a21e074e58748afa4b9c9 100644
--- a/chrome/renderer/net/prescient_networking_dispatcher.cc
+++ b/chrome/renderer/net/prescient_networking_dispatcher.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/renderer/net/prescient_networking_dispatcher.h"
 
+#include "base/strings/utf_string_conversions.h"
 #include "chrome/common/render_messages.h"
 #include "content/public/renderer/render_thread.h"
 
@@ -12,6 +13,16 @@ using WebKit::WebPrescientNetworking;
 PrescientNetworkingDispatcher::~PrescientNetworkingDispatcher() {
 }
 
+void PrescientNetworkingDispatcher::prefetchDNS(
+    const WebKit::WebString& hostname) {
+  if (hostname.isEmpty())
+    return;
+
+  std::string hostname_utf8;
+  UTF16ToUTF8(hostname.data(), hostname.length(), &hostname_utf8);
+  net_predictor_.Resolve(hostname_utf8.data(), hostname_utf8.length());
+}
+
 void PrescientNetworkingDispatcher::preconnect(
     const WebKit::WebURL& url,
     WebKit::WebPreconnectMotivation motivation) {