[NoStatePrefetch] Track redirects in UMA

chrome/browser/prerender/prerender_histograms.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 CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 90 matching lines @@
                                       base::TimeDelta time) const;
 
   // Record the bytes in the prerender, whether it was used or not, and the
   // total number of bytes fetched for this profile since the last call to
   // RecordBytes.
   void RecordNetworkBytes(Origin origin,
                           bool used,
                           int64_t prerender_bytes,
                           int64_t profile_bytes) const;
 
-  // Record resources loaded by NoStatePrefetch.
-  void RecordResourcePrefetch(Origin origin,
-                              bool is_main_resource,
-                              bool is_no_store) const;
+  // Called when a NoStatePrefetch request has received a response (including
+  // redirects). May be called several times per resource, in case of redirects.
+  void RecordPrefetchResponseReceived(Origin origin,
+                                      bool is_main_resource,
+                                      bool is_redirect,
+                                      bool is_no_store) const;
+
+  // Called when a NoStatePrefetch resource has been loaded. This is called only
+  // once per resource, when all redirects have been resolved.
+  void RecordPrefetchRedirectCount(Origin origin,
+                                   bool is_main_resource,
+                                   int redirect_count) const;
 
  private:
   base::TimeTicks GetCurrentTimeTicks() const;
 
   // Returns the time elapsed since the last prerender happened.
   base::TimeDelta GetTimeSinceLastPrerender() const;
 
   // Returns whether the PrerenderManager is currently within the prerender
   // window - effectively, up to 30 seconds after a prerender tag has been
   // observed.
@@ skipping 21 matching lines @@
   bool seen_pageload_started_after_prerender_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderHistograms);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_