predictors: Put manifests for ResourcePrefetchPredictor behind a flag.

chrome/browser/predictors/resource_prefetch_predictor_unittest.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_predictor.h"
 
 #include <iostream>
 #include <memory>
 #include <utility>
 
@@ skipping 218 matching lines @@
 
   void ResetPredictor() {
     ResourcePrefetchPredictorConfig config;
     config.max_urls_to_track = 3;
     config.max_hosts_to_track = 2;
     config.min_url_visit_count = 2;
     config.max_resources_per_entry = 4;
     config.max_consecutive_misses = 2;
     config.min_resource_confidence_to_trigger_prefetch = 0.5;
     config.is_url_learning_enabled = true;
+    config.is_manifests_enabled = true;
 
     config.mode |= ResourcePrefetchPredictorConfig::LEARNING;
     predictor_.reset(new ResourcePrefetchPredictor(config, profile_.get()));
     predictor_->set_mock_tables(mock_tables_);
   }
 
   void InitializeSampleData();
   void TestRedirectStatusHistogram(
       const std::string& predictor_initial_key,
       const std::string& predictor_key,
@@ skipping 1610 matching lines @@
   predictor_->host_table_cache_->insert(
       std::make_pair(google.primary_key(), google));
 
   predictor_->StartPrefetching(GURL(main_frame_url), PrefetchOrigin::EXTERNAL);
   predictor_->StopPrefetching(GURL(main_frame_url));
   histogram_tester_->ExpectTotalCount(
       internal::kResourcePrefetchPredictorPrefetchingDurationHistogram, 1);
 }
 
 }  // namespace predictors