[Prerender] Restore request priorities when swapped in

content/browser/loader/resource_dispatcher_host_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 
 #include <stddef.h>
 
@@ skipping 480 matching lines @@
   DCHECK(http_header_interceptor_map_.find(http_header) ==
          http_header_interceptor_map_.end());
 
   HeaderInterceptorInfo interceptor_info;
   interceptor_info.starts_with = starts_with;
   interceptor_info.interceptor = interceptor;
 
   http_header_interceptor_map_[http_header] = interceptor_info;
 }
 
+void ResourceDispatcherHostImpl::ReprioritizeRequest(
+    net::URLRequest* request,
+    net::RequestPriority priority) {
+  scheduler_->ReprioritizeRequest(request, priority);
+}
+
 void ResourceDispatcherHostImpl::Shutdown() {
   DCHECK(main_thread_task_runner_->BelongsToCurrentThread());
   io_thread_task_runner_->PostTask(
       FROM_HERE, base::Bind(&ResourceDispatcherHostImpl::OnShutdown,
                             base::Unretained(this)));
 }
 
 std::unique_ptr<ResourceHandler>
 ResourceDispatcherHostImpl::CreateResourceHandlerForDownload(
     net::URLRequest* request,
@@ skipping 2116 matching lines @@
                                  &throttles);
     if (!throttles.empty()) {
       handler.reset(new ThrottlingResourceHandler(std::move(handler), request,
                                                   std::move(throttles)));
     }
   }
   return handler;
 }
 
 }  // namespace content