Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/predictors/resource_prefetch_predictor.h

 // Copyright 2014 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_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_H_
 #define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/time/time.h"
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_tables.h"
 #include "chrome/browser/predictors/resource_prefetcher.h"
+#include "components/history/core/browser/history_service_observer.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/common/resource_type.h"
 #include "url/gurl.h"
 
 class PredictorsHandler;
 class Profile;
 
@@ skipping 37 matching lines @@
 //   ResourcePrefetcherManager, and issues net::URLRequest to fetch resources.
 //
 // TODO(shishir): Do speculative prefetching for https resources and/or https
 // main frame urls.
 // TODO(zhenw): Currently only main frame requests/redirects/responses are
 // recorded. Consider recording sub-frame responses independently or together
 // with main frame.
 class ResourcePrefetchPredictor
     : public KeyedService,
       public content::NotificationObserver,
+      public history::HistoryServiceObserver,
       public base::SupportsWeakPtr<ResourcePrefetchPredictor> {
  public:
   // Stores the data that we need to get from the URLRequest.
   struct URLRequestSummary {
     URLRequestSummary();
     URLRequestSummary(const URLRequestSummary& other);
     ~URLRequestSummary();
 
     NavigationID navigation_id;
     GURL resource_url;
@@ skipping 31 matching lines @@
   // Called when the main frame of a page completes loading.
   void RecordMainFrameLoadComplete(const NavigationID& navigation_id);
 
   // Called by ResourcePrefetcherManager to notify that prefetching has finished
   // for a navigation. Should take ownership of |requests|.
   virtual void FinishedPrefetchForNavigation(
       const NavigationID& navigation_id,
       PrefetchKeyType key_type,
       ResourcePrefetcher::RequestVector* requests);
 
+  // history::HistoryServiceObserver:
+  void OnHistoryServiceLoaded(HistoryService* history_service) override;
+
  private:
   friend class ::PredictorsHandler;
   friend class ResourcePrefetchPredictorTest;
 
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, DeleteUrls);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            LazilyInitializeEmpty);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            LazilyInitializeWithData);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
@@ skipping 142 matching lines @@
       const ResourcePrefetcher::RequestVector& predicted,
       const std::map<GURL, bool>& actual,
       size_t total_resources_fetched_from_network,
       size_t max_assumed_prefetched) const;
 
   // Used for testing to inject mock tables.
   void set_mock_tables(scoped_refptr<ResourcePrefetchPredictorTables> tables) {
     tables_ = tables;
   }
 
+  // If HistoryService exists and its Backend is loaded,
+  // calls the OnHistoryAndCacheLoaded.
+  // Else wait for the OnHistoryServiceLoaded event.
+  void CheckForHistoryService();
+
   Profile* const profile_;
   ResourcePrefetchPredictorConfig const config_;
   InitializationState initialization_state_;
   scoped_refptr<ResourcePrefetchPredictorTables> tables_;
   scoped_refptr<ResourcePrefetcherManager> prefetch_manager_;
   content::NotificationRegistrar notification_registrar_;
   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.
   scoped_ptr<PrefetchDataMap> url_table_cache_;
   scoped_ptr<PrefetchDataMap> host_table_cache_;
 
   ResultsMap results_map_;
   STLValueDeleter<ResultsMap> results_map_deleter_;
 
+  ScopedObserver<HistoryService, history::HistoryServiceObserver>
+      history_service_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(ResourcePrefetchPredictor);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_H_