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 fa10df6407c652b0b04392097698a1161857ddc9..f363e0f19252e40b1df0ac63afef4af3e5d89ce5 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -295,6 +295,14 @@ void RendererWebKitPlatformSupportImpl::prefetchHostName(
       hostname_utf8.data(), hostname_utf8.length());
 }
 
+void RendererWebKitPlatformSupportImpl::preconnect(
+    const WebKit::WebURL& url,
+    WebKit::WebPreconnectMotivation motivation,
+    uint32_t motivationVariationId) {
+  GetContentClient()->renderer()->Preconnect(
+      GURL(url), motivation, motivationVariationId);
+}
+
 bool
 RendererWebKitPlatformSupportImpl::CheckPreparsedJsCachingEnabled() const {
   static bool checked = false;