predictors: Refactor resource_prefetch_predictor triggering.

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 <utility>
 
+#include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "components/keyed_service/core/keyed_service.h"
+#include "url/gurl.h"
 
 class Profile;
 
 namespace predictors {
 
 class ResourcePrefetchPredictor;
 
 // 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,
                          public base::SupportsWeakPtr<LoadingPredictor> {
  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   // Indicates that a page load hint is no longer active.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);
 
   // Starts initialization, will complete asynchronously.
   void StartInitialization();
 
   // Don't use, internal only.
   ResourcePrefetchPredictor* resource_prefetch_predictor() const;
 
   // KeyedService:
   void Shutdown() override;
 
+  void OnMainFrameRequest(
+      const ResourcePrefetchPredictor::URLRequestSummary& summary);
+  void OnMainFrameRedirect(
+      const ResourcePrefetchPredictor::URLRequestSummary& summary);
+  void OnMainFrameResponse(
+      const ResourcePrefetchPredictor::URLRequestSummary& summary);
+
  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);
+
+  // 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::map<GURL, base::TimeTicks> active_hints_;
+  // Initial URL.
+  std::map<NavigationID, GURL> active_navigations_;
+
+  friend class LoadingPredictorTest;

[alexilin, 2017/05/31 16:02:03]

nit:
Usually we put friends declarations closer to the beginning of the private
section. It's up to you.

+  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);
 
   DISALLOW_COPY_AND_ASSIGN(LoadingPredictor);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_LOADING_PREDICTOR_H_