[Prerender] Restore request priorities when swapped in

content/browser/loader/resource_scheduler.h

 // 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.
 
 #ifndef CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
 #define CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 79 matching lines @@
 
   // Called when we received a response to a http request that was served
   // from a proxy using SPDY.
   void OnReceivedSpdyProxiedHttpResponse(int child_id, int route_id);
 
   // Client functions:
 
   // Returns true if at least one client is currently loading.
   bool HasLoadingClients() const;
 
-  // Update the priority for |request|. Modifies request->priority(), and may
+  // Updates the priority for |request|. Modifies request->priority(), and may
   // start the request loading if it wasn't already started.
+  // If the scheduler does not know about the request, |new_priority| is set but
+  // |intra_priority_value| is ignored.
   void ReprioritizeRequest(net::URLRequest* request,
                            net::RequestPriority new_priority,
                            int intra_priority_value);
+  // Same as above, but keeps the existing intra priority value.
+  void ReprioritizeRequest(net::URLRequest* request,
+                           net::RequestPriority new_priority);
 
  private:
   // Returns the maximum number of delayable requests to all be in-flight at
   // any point in time (across all hosts).
   size_t max_num_delayable_requests() const {
     return max_num_delayable_requests_;
   }
 
   class RequestQueue;
   class ScheduledResourceRequest;
@@ skipping 29 matching lines @@
   // start resource requests.
   bool yielding_scheduler_enabled_;
   int max_requests_before_yielding_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceScheduler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_RESOURCE_SCHEDULER_H_