Reland of predictors: Basic browsertest checks predictor learning.

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 <stddef.h>
 
 #include <map>
@@ skipping 145 matching lines @@
   void StopPrefetching(const GURL& main_frame_url);
 
   // Sets the |observer| to be notified when the resource prefetch predictor
   // data changes. Previously registered observer will be discarded. Call
   // this with nullptr parameter to de-register observer.
   void SetObserverForTesting(TestObserver* observer);
 
  private:
   friend class ::PredictorsHandler;
   friend class ResourcePrefetchPredictorTest;
+  friend class ResourcePrefetchPredictorBrowserTest;
 
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, DeleteUrls);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            LazilyInitializeEmpty);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            LazilyInitializeWithData);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            NavigationNotRecorded);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, NavigationUrlInDB);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, NavigationUrlNotInDB);
@@ skipping 182 matching lines @@
 // has changed. All methods are invoked on the UI thread.
 class TestObserver {
  public:
   // De-registers itself from |predictor_| on destruction.
   virtual ~TestObserver();
 
   virtual void OnNavigationLearned(
       size_t url_visit_count,
       const ResourcePrefetchPredictor::PageRequestSummary& summary) {}
 
+  virtual void OnPredictorInitialized() {}
+
  protected:
   // |predictor| must be non-NULL and has to outlive the TestObserver.
   // Also the predictor must not have a TestObserver set.
   explicit TestObserver(ResourcePrefetchPredictor* predictor);
 
  private:
   ResourcePrefetchPredictor* predictor_;
 
   DISALLOW_COPY_AND_ASSIGN(TestObserver);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_H_