Add comment explaining fix and added explicit HistoryService dependency in predictor.

chrome/browser/predictors/resource_prefetch_predictor_factory.cc

 // 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.
 
 #include "chrome/browser/predictors/resource_prefetch_predictor_factory.h"
 
+#include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/predictors/predictor_database_factory.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_dependency_manager.h"
 
 namespace predictors {
 
 // static
 ResourcePrefetchPredictor* ResourcePrefetchPredictorFactory::GetForProfile(
     Profile* profile) {
   return static_cast<ResourcePrefetchPredictor*>(
       GetInstance()->GetServiceForProfile(profile, true));
 }
 
 // static
 ResourcePrefetchPredictorFactory*
 ResourcePrefetchPredictorFactory::GetInstance() {
   return Singleton<ResourcePrefetchPredictorFactory>::get();
 }
 
 ResourcePrefetchPredictorFactory::ResourcePrefetchPredictorFactory()
     : ProfileKeyedServiceFactory("ResourcePrefetchPredictor",
                                  ProfileDependencyManager::GetInstance()) {
-  // TODO(shishir): Uncomment this when crbug.com/97804 is fixed.
-  // DependsOn(HistoryServiceFactory::GetInstance());
+  DependsOn(HistoryServiceFactory::GetInstance());
   DependsOn(PredictorDatabaseFactory::GetInstance());
 }
 
 ResourcePrefetchPredictorFactory::~ResourcePrefetchPredictorFactory() {}
 
 ProfileKeyedService*
     ResourcePrefetchPredictorFactory::BuildServiceInstanceFor(
         Profile* profile) const {
   return ResourcePrefetchPredictor::IsEnabled(profile) ?
           new ResourcePrefetchPredictor(ResourcePrefetchPredictor::Config(),
                                         profile) :
           NULL;
 }
 
 }  // namespace predictors