Add a browsertest suite for net predictor

chrome/browser/net/predictor.h

 // Copyright (c) 2012 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.
 
 // A Predictor object is instantiated once in the browser process, and manages
 // both preresolution of hostnames, as well as TCP/IP preconnection to expected
 // subresources.
 // Most hostname lists are provided by the renderer processes, and include URLs
 // that *might* be used in the near future by the browsing user.  One goal of
 // this class is to cause the underlying DNS structure to lookup a hostname
@@ skipping 57 matching lines @@
 typedef std::map<GURL, UrlInfo> Results;
 
 // An observer for testing.
 class PredictorObserver {
  public:
   virtual ~PredictorObserver() {}
 
   virtual void OnPreconnectUrl(const GURL& original_url,
                                const GURL& first_party_for_cookies,
                                UrlInfo::ResolutionMotivation motivation,
-                               int count) = 0;
+                               int count) {}
+  virtual void OnLearnFromNavigation(const GURL& referring_url,
+                                     const GURL& target_url) {}

[mmenke, 2016/04/22 16:29:25]

Pre-existing issue, but this file should forward declare GURL - or actually,
probably include it, since one method returns a GURL.

[Charlie Harrison, 2016/04/28 16:29:51]

Done.

 };
 
 // Predictor is constructed during Profile construction (on the UI thread),
 // but it is destroyed on the IO thread when ProfileIOData goes away. All of
 // its core state and functionality happens on the IO thread. The only UI
 // methods are initialization / shutdown related (including preconnect
 // initialization), or convenience methods that internally forward calls to
 // the IO thread.
 class Predictor {
  public:
@@ skipping 211 matching lines @@
   }
 
   bool preconnect_enabled() const {
     return preconnect_enabled_;
   }
 
   bool predictor_enabled() const {
     return predictor_enabled_;
   }
 
+  // Used only for testing.

[mmenke, 2016/04/22 16:29:24]

Maybe add "Overrides command line flag to disable preconnect, which is added the
browser test fixture."

+  void set_preconnect_enabled_for_test(bool preconnect_enabled) {
+    preconnect_enabled_ = preconnect_enabled;
+  }
 
  private:
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, BenefitLookupTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, ShutdownWhenResolutionIsPendingTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, SingleLookupTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, ConcurrentLookupTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, MassiveConcurrentLookupTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, PriorityQueuePushPopTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, PriorityQueueReorderTest);
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, ReferrerSerializationTrimTest);
@@ skipping 237 matching lines @@
   // The SSLConfigService we query SNI support from (used in querying HSTS
   // redirects).
   net::SSLConfigService* ssl_config_service_;
 
   // The ProxyService, used to determine whether preresolve is useful.
   net::ProxyService* proxy_service_;
 
   // Are we currently using preconnection, rather than just DNS resolution, for
   // subresources and omni-box search URLs.
   // This is false if and only if disabled by a command line switch.
-  const bool preconnect_enabled_;
+  bool preconnect_enabled_;
 
   // Most recent suggestion from Omnibox provided via AnticipateOmniboxUrl().
   std::string last_omnibox_host_;
 
   // The time when the last preresolve was done for last_omnibox_host_.
   base::TimeTicks last_omnibox_preresolve_;
 
   // The number of consecutive requests to AnticipateOmniboxUrl() that suggested
   // preconnecting (because it was to a search service).
   int consecutive_omnibox_preconnect_count_;
@@ skipping 36 matching lines @@
 
  private:
   // These member functions return True for unittests.
   bool CanPrefetchAndPrerender() const override;
   bool CanPreresolveAndPreconnect() const override;
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PREDICTOR_H_