predictors: Add origin learning.

chrome/browser/predictors/resource_prefetch_common.cc

 // 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.
 
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 
 #include <string>
 #include <tuple>
 
 #include "base/metrics/field_trial_params.h"
@@ skipping 114 matching lines @@
   return tab_id == rhs.tab_id && main_frame_url == rhs.main_frame_url;
 }
 
 ResourcePrefetchPredictorConfig::ResourcePrefetchPredictorConfig()
     : mode(0),
       max_navigation_lifetime_seconds(60),
       max_urls_to_track(500),
       max_hosts_to_track(200),
       min_url_visit_count(2),
       max_resources_per_entry(50),
+      max_origins_per_entry(50),
       max_consecutive_misses(3),
       min_resource_confidence_to_trigger_prefetch(0.7f),
       min_resource_hits_to_trigger_prefetch(2),
       max_prefetches_inflight_per_navigation(5),
       max_prefetches_inflight_per_host_per_navigation(3),
-      is_url_learning_enabled(false) {
-}
+      is_url_learning_enabled(false),
+      is_origin_prediction_enabled(false) {}

[alexilin, 2017/04/10 14:58:27]

nit:
Could you add the check of default value for |is_origin_prediction_enabled| to
resource_prefetch_common_unittest.cc?
To be precise, the function TestIsDefaultExtraConfig().

[Benoit L, 2017/04/11 09:04:05]

Done.

 
 ResourcePrefetchPredictorConfig::ResourcePrefetchPredictorConfig(
     const ResourcePrefetchPredictorConfig& other) = default;
 
 ResourcePrefetchPredictorConfig::~ResourcePrefetchPredictorConfig() {
 }
 
 bool ResourcePrefetchPredictorConfig::IsLearningEnabled() const {
   return (mode & LEARNING) > 0;
 }
@@ skipping 33 matching lines @@
 
 bool ResourcePrefetchPredictorConfig::IsMoreResourcesEnabledForTest() const {
   return max_resources_per_entry == 100;
 }
 
 bool ResourcePrefetchPredictorConfig::IsSmallDBEnabledForTest() const {
   return max_urls_to_track == 200 && max_hosts_to_track == 100;
 }
 
 }  // namespace predictors