predictors: move ResourcePrefetcher handling to LoadingPredictor.

chrome/browser/predictors/loading_predictor.h

 // Copyright 2017 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_LOADING_PREDICTOR_H_
 #define CHROME_BROWSER_PREDICTORS_LOADING_PREDICTOR_H_
 
 #include <map>
 #include <memory>
+#include <string>
 #include <utility>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "chrome/browser/predictors/loading_data_collector.h"
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "chrome/browser/predictors/resource_prefetcher.h"
+#include "chrome/browser/profiles/profile.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "url/gurl.h"
 
 class Profile;
 
 namespace predictors {
 
 class ResourcePrefetchPredictor;
 class LoadingStatsCollector;
+class TestLoadingObserver;
 
 // Entry point for the Loading predictor.
 // From a high-level request (GURL and motivation) and a database of historical
 // data, initiates predictive actions to speed up page loads.
 //
 // Also listens to main frame requests/redirects/responses to initiate and
 // cancel page load hints.
 //
 // See ResourcePrefetchPredictor for a description of the resource prefetch
 // predictor.
 //
 // All methods must be called from the UI thread.
-class LoadingPredictor : public KeyedService {
+class LoadingPredictor : public KeyedService,
+                         public ResourcePrefetcher::Delegate {
  public:
   LoadingPredictor(const LoadingPredictorConfig& config, Profile* profile);
   ~LoadingPredictor() override;
 
   // Hints that a page load is expected for |url|, with the hint coming from a
   // given |origin|. May trigger actions, such as prefetch and/or preconnect.
   void PrepareForPageLoad(const GURL& url, HintOrigin origin);
 
   // Indicates that a page load hint is no longer active.
   void CancelPageLoadHint(const GURL& url);
@@ skipping 12 matching lines @@
       const ResourcePrefetchPredictor::URLRequestSummary& summary);
   void OnMainFrameRedirect(
       const ResourcePrefetchPredictor::URLRequestSummary& summary);
   void OnMainFrameResponse(
       const ResourcePrefetchPredictor::URLRequestSummary& summary);
 
   base::WeakPtr<LoadingPredictor> GetWeakPtr() {
     return weak_factory_.GetWeakPtr();
   }
 
+  // ResourcePrefetcher::Delegate:
+  void ResourcePrefetcherFinished(
+      ResourcePrefetcher* prefetcher,
+      std::unique_ptr<ResourcePrefetcher::PrefetcherStats> stats) override;
+
+  // Sets the |observer| to be notified when prefetches start and
+  // finish. A previously registered observer will be discarded. Call this with
+  // a nullptr parameter to de-register the observer.
+  void SetObserverForTesting(TestLoadingObserver* observer);
+
  private:
   // Cancels an active hint, from its iterator inside |active_hints_|. If the
   // iterator is .end(), does nothing. Returns the iterator after deletion of
   // the entry.
   std::map<GURL, base::TimeTicks>::iterator CancelActiveHint(
       std::map<GURL, base::TimeTicks>::iterator hint_it);
   void CleanupAbandonedHintsAndNavigations(const NavigationID& navigation_id);
 
+  // May start a prefetch for |url| with the data from |prediction|, and a
+  // given hint |origin|. A new prefetch may not start if there is already
+  // one in flight, for instance.
+  void MaybeAddPrefetch(const GURL& url,
+                        const ResourcePrefetchPredictor::Prediction& prediction,
+                        HintOrigin origin);
+
+  // If a prefetch exists for |url|, stop it.
+  void MaybeRemovePrefetch(const GURL& url);
+
   // For testing.
   void set_mock_resource_prefetch_predictor(
       std::unique_ptr<ResourcePrefetchPredictor> predictor) {
     resource_prefetch_predictor_ = std::move(predictor);
   }
 
   LoadingPredictorConfig config_;
   Profile* profile_;
   std::unique_ptr<ResourcePrefetchPredictor> resource_prefetch_predictor_;
   std::unique_ptr<LoadingStatsCollector> stats_collector_;
   std::unique_ptr<LoadingDataCollector> loading_data_collector_;
   std::map<GURL, base::TimeTicks> active_hints_;
   // Initial URL.
   std::map<NavigationID, GURL> active_navigations_;
+  // The value is {prefetcher, already deleted}.
+  std::map<std::string, std::pair<std::unique_ptr<ResourcePrefetcher>, bool>>
+      prefetches_;
+  TestLoadingObserver* observer_;
 
   friend class LoadingPredictorTest;
   FRIEND_TEST_ALL_PREFIXES(LoadingPredictorTest,
                            TestMainFrameResponseCancelsHint);
   FRIEND_TEST_ALL_PREFIXES(LoadingPredictorTest,
                            TestMainFrameRequestCancelsStaleNavigations);
   FRIEND_TEST_ALL_PREFIXES(LoadingPredictorTest,
                            TestMainFrameResponseClearsNavigations);
   FRIEND_TEST_ALL_PREFIXES(LoadingPredictorTest,
                            TestMainFrameRequestDoesntCancelExternalHint);
   FRIEND_TEST_ALL_PREFIXES(LoadingPredictorTest,
                            TestDontTrackNonPrefetchableUrls);
 
   base::WeakPtrFactory<LoadingPredictor> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadingPredictor);
 };
 
+// An interface used to notify that data in the LoadingPredictor has
+// changed. All methods are called on the UI thread.
+class TestLoadingObserver {
+ public:
+  // De-registers itself from |predictor_| on destruction.
+  virtual ~TestLoadingObserver();
+
+  virtual void OnPrefetchingStarted(const GURL& main_frame_url) {}
+
+  virtual void OnPrefetchingStopped(const GURL& main_frame_url) {}
+
+  virtual void OnPrefetchingFinished(const GURL& main_frame_url) {}
+
+ protected:
+  // |predictor| must be non-NULL and has to outlive the LoadingTestObserver.
+  // Also the predictor must not have a LoadingTestObserver set.
+  explicit TestLoadingObserver(LoadingPredictor* predictor);
+
+ private:
+  LoadingPredictor* predictor_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestLoadingObserver);
+};
+
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_LOADING_PREDICTOR_H_