Add a Dns preresolve interface in //content

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 8bce7931fe340b1854d16ecbf78f9da2de6de6d4..1c0273ac4770e807bf7f34dd7d3b363a383c0344 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -55,6 +55,7 @@
 #include "content/browser/loader/navigation_url_loader_impl_core.h"
 #include "content/browser/loader/power_save_block_resource_throttle.h"
 #include "content/browser/loader/redirect_to_file_resource_handler.h"
+#include "content/browser/loader/resource_hints_controller.h"
 #include "content/browser/loader/resource_message_filter.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/browser/loader/stream_resource_handler.h"
@@ -1144,6 +1145,7 @@ void ResourceDispatcherHostImpl::DidFinishLoading(ResourceLoader* loader) {
 
 void ResourceDispatcherHostImpl::OnInit() {
   scheduler_.reset(new ResourceScheduler);
+  resource_hints_controller_.reset(new ResourceHintsController);
 }
 
 void ResourceDispatcherHostImpl::OnShutdown() {
@@ -1173,6 +1175,7 @@ void ResourceDispatcherHostImpl::OnShutdown() {
   }
 
   scheduler_.reset();
+  resource_hints_controller_.reset();
 }
 
 bool ResourceDispatcherHostImpl::OnMessageReceived(