[Prerender] Restore request priorities when swapped in

content/public/browser/resource_dispatcher_host.h

Index: content/public/browser/resource_dispatcher_host.h
diff --git a/content/public/browser/resource_dispatcher_host.h b/content/public/browser/resource_dispatcher_host.h
index 4838b48766d2999da16400a6ff0c42405cae496f..6f2f26f3a10508ea0b7676363e8a257531150632 100644
--- a/content/public/browser/resource_dispatcher_host.h
+++ b/content/public/browser/resource_dispatcher_host.h
@@ -12,6 +12,7 @@
 
 #include "base/callback_forward.h"
 #include "content/common/content_export.h"
+#include "net/base/request_priority.h"
 
 namespace net {
 class URLRequest;
@@ -84,6 +85,11 @@ class CONTENT_EXPORT ResourceDispatcherHost {
                                    const std::string& starts_with,
                                    const InterceptorCallback& interceptor) = 0;
 
+  // Updates the priority for |request|. Modifies request->priority(), and may
+  // start the request loading if it wasn't already started.
+  virtual void ReprioritizeRequest(net::URLRequest* request,
+                                   net::RequestPriority priority) = 0;
+
  protected:
   virtual ~ResourceDispatcherHost() {}
 };