Remove PrerenderResourceThrottle and related infrastructure.

chrome/browser/prerender/prerender_tracker.h

Index: chrome/browser/prerender/prerender_tracker.h
diff --git a/chrome/browser/prerender/prerender_tracker.h b/chrome/browser/prerender/prerender_tracker.h
index 56d5dffc8fc176825c4448f902572f0d32c91023..c30da905f9fad8e37ba14258d7658af1254587dc 100644
--- a/chrome/browser/prerender/prerender_tracker.h
+++ b/chrome/browser/prerender/prerender_tracker.h
@@ -79,15 +79,6 @@ class PrerenderTracker {
   bool TryCancelOnIOThread(int child_id, int route_id,
                            FinalStatus final_status);
 
-  // Potentially delay a resource request on the IO thread to prevent a double
-  // get.  When this method returns true, the callback will be run later to
-  // indicate if the request should be allowed or canceled.
-  bool PotentiallyDelayRequestOnIOThread(
-      const GURL& gurl,
-      int child_id,
-      int route_id,
-      const CheckURLCallback& callback);
-
   void AddPrerenderURLOnUIThread(const GURL& url);
   void RemovePrerenderURLsOnUIThread(const std::vector<GURL>& urls);