Redirect handling in the resource_prefetch_predictor.

chrome/browser/predictors/resource_prefetch_predictor.h

Index: chrome/browser/predictors/resource_prefetch_predictor.h
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.h b/chrome/browser/predictors/resource_prefetch_predictor.h
index 82fdfee2fc000862a6e8400c43b4f4801926062a..51e34078b79feca6f3661a169712068471735fc1 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.h
+++ b/chrome/browser/predictors/resource_prefetch_predictor.h
@@ -99,6 +99,15 @@ class ResourcePrefetchPredictor
                                   URLRequestSummary* summary);
   };
 
+  // Stores information about inflight navigations.
+  struct Navigation {

[pasko, 2016/09/22 14:27:09]

The name 'Navigation' looks a bit generic, so it slightly complicates reading
resource_prefetch_predictor.cc. RedirectChain would be more readable, at least
to me.

[alexilin, 2016/09/22 16:48:19]

I don't think that 'RedirectChain' is also a good name.
Because this structure holds the all information that
'ResourcePrefetchPredictor' collects within single navigation.
'subresource_requests' contains all requests to subresources as well, so
'RedirectChain' name isn't relevant.

Actually, this struct could be moved in private section, because it isn't used
outside 'ResourcePrefetchPredictor'. So then we could keep 'NavigationInfo' or
'NavigationData' name.

[pasko, 2016/09/26 12:28:15]

I would also prefer moving it into the implementation if it is possible.

How about 'PageRequestSummary' or 'PageLoadRequestInfo' or some variation of
these? My understanding of 'Navigation' does not include subresources, only
remotely relevant.

[alexilin, 2016/09/27 14:52:45]

Renamed to 'PageRequestSummary' and moved into private section of
ResourcePrefetchPredictor class.
Done.

+    explicit Navigation(const GURL& initial_url);
+    ~Navigation();
+
+    GURL initial_url;
+    std::vector<URLRequestSummary> subresource_requests;
+  };
+
   ResourcePrefetchPredictor(const ResourcePrefetchPredictorConfig& config,
                             Profile* profile);
   ~ResourcePrefetchPredictor() override;
@@ -153,6 +162,8 @@ class ResourcePrefetchPredictor
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, NavigationUrlNotInDB);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            NavigationUrlNotInDBAndDBFull);
+  FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, RedirectUrlNotInDB);
+  FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, RedirectUrlInDB);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, OnMainFrameRequest);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, OnMainFrameRedirect);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
@@ -182,8 +193,10 @@ class ResourcePrefetchPredictor
 
   typedef ResourcePrefetchPredictorTables::PrefetchData PrefetchData;
   typedef ResourcePrefetchPredictorTables::PrefetchDataMap PrefetchDataMap;
-  typedef std::map<NavigationID, linked_ptr<std::vector<URLRequestSummary> > >
-      NavigationMap;
+
+  typedef ResourcePrefetchPredictorTables::RedirectDataMap RedirectDataMap;
+
+  typedef std::map<NavigationID, std::unique_ptr<Navigation>> NavigationMap;
   typedef std::map<NavigationID, std::unique_ptr<Result>> ResultsMap;
 
   // Returns true if the main page request is supported for prediction.
@@ -238,9 +251,11 @@ class ResourcePrefetchPredictor
   void StartInitialization();
 
   // Callback for task to read predictor database. Takes ownership of
-  // |url_data_map| and |host_data_map|.
+  // all arguments.
   void CreateCaches(std::unique_ptr<PrefetchDataMap> url_data_map,
-                    std::unique_ptr<PrefetchDataMap> host_data_map);
+                    std::unique_ptr<PrefetchDataMap> host_data_map,
+                    std::unique_ptr<RedirectDataMap> url_redirect_data_map,
+                    std::unique_ptr<RedirectDataMap> host_redirect_data_map);
 
   // Called during initialization when history is read and the predictor
   // database has been read.
@@ -261,20 +276,33 @@ class ResourcePrefetchPredictor
   // Callback for GetUrlVisitCountTask.
   void OnVisitCountLookup(size_t visit_count,
                           const NavigationID& navigation_id,
-                          const std::vector<URLRequestSummary>& requests);
+                          const Navigation& navigation);
 
   // Removes the oldest entry in the input |data_map|, also deleting it from the
   // predictor database.
   void RemoveOldestEntryInPrefetchDataMap(PrefetchKeyType key_type,
                                           PrefetchDataMap* data_map);
 
+  void RemoveOldestEntryInRedirectDataMap(PrefetchKeyType key_type,
+                                          RedirectDataMap* data_map);
+
   // Merges resources in |new_resources| into the |data_map| and correspondingly
-  // updates the predictor database.
+  // updates the predictor database. Also calls LearnRedirect if relevant.
   void LearnNavigation(const std::string& key,
                        PrefetchKeyType key_type,
                        const std::vector<URLRequestSummary>& new_resources,
                        size_t max_data_map_size,
-                       PrefetchDataMap* data_map);
+                       PrefetchDataMap* data_map,
+                       const std::string& redirect_origin_key,
+                       RedirectDataMap* redirect_map);
+
+  // Updates information about final redirect destination for |key| in
+  // |redirect_map| and correspondingly updates the predictor database
+  void LearnRedirect(const std::string& key,
+                     PrefetchKeyType key_type,
+                     const std::string& final_redirect,
+                     size_t max_redirect_map_size,
+                     RedirectDataMap* redirect_map);
 
   // Reports overall page load time.
   void ReportPageLoadTimeStats(base::TimeDelta plt) const;
@@ -330,13 +358,13 @@ class ResourcePrefetchPredictor
   scoped_refptr<ResourcePrefetcherManager> prefetch_manager_;
   base::CancelableTaskTracker history_lookup_consumer_;
 
-  // Map of all the navigations in flight to their resource requests.
-  NavigationMap inflight_navigations_;
-
   // Copy of the data in the predictor tables.
   std::unique_ptr<PrefetchDataMap> url_table_cache_;
   std::unique_ptr<PrefetchDataMap> host_table_cache_;
+  std::unique_ptr<RedirectDataMap> url_redirect_table_cache_;
+  std::unique_ptr<RedirectDataMap> host_redirect_table_cache_;
 
+  NavigationMap inflight_navigations_;
   ResultsMap results_map_;
 
   ScopedObserver<history::HistoryService, history::HistoryServiceObserver>