Implement WebPrescientNetworking to trigger preconnect from Blink

content/renderer/renderer_webkitplatformsupport_impl.cc

Index: content/renderer/renderer_webkitplatformsupport_impl.cc
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index 121096495119d3e5a392d9fd44ce11fa62cd3d8f..6a53c3b7136bc9b70937ffb23da5e9563a6cdc7d 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -295,6 +295,11 @@ void RendererWebKitPlatformSupportImpl::prefetchHostName(
       hostname_utf8.data(), hostname_utf8.length());
 }
 
+WebKit::WebPrescientNetworking*
+RendererWebKitPlatformSupportImpl::prescientNetworking() {
+  return GetContentClient()->renderer()->GetPrescientNetworking();
+}
+
 bool
 RendererWebKitPlatformSupportImpl::CheckPreparsedJsCachingEnabled() const {
   static bool checked = false;