Make extensions DSE persistent in browser prefs

chrome/browser/search_engines/chrome_template_url_service_client.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_SEARCH_ENGINES_CHROME_TEMPLATE_URL_SERVICE_CLIENT_H_
 #define CHROME_BROWSER_SEARCH_ENGINES_CHROME_TEMPLATE_URL_SERVICE_CLIENT_H_
 
 #include "base/macros.h"
 #include "base/scoped_observer.h"
 #include "components/history/core/browser/history_service_observer.h"
 #include "components/search_engines/template_url_service_client.h"
 
 namespace history {
 class HistoryService;
 }
 
+class ExtensionPrefValueMap;
+
 // ChromeTemplateURLServiceClient provides keyword related history
 // functionality for TemplateURLService.
 class ChromeTemplateURLServiceClient : public TemplateURLServiceClient,
                                        public history::HistoryServiceObserver {
  public:
-  explicit ChromeTemplateURLServiceClient(
-      history::HistoryService* history_service);
+  ChromeTemplateURLServiceClient(
+      history::HistoryService* history_service,
+      ExtensionPrefValueMap* extension_prefs_value_map);
   ~ChromeTemplateURLServiceClient() override;
 
   // TemplateURLServiceClient:
   void Shutdown() override;
   void SetOwner(TemplateURLService* owner) override;
   void DeleteAllSearchTermsForKeyword(history::KeywordID keyword_Id) override;
   void SetKeywordSearchTermsForURL(const GURL& url,
                                    TemplateURLID id,
                                    const base::string16& term) override;
   void AddKeywordGeneratedVisit(const GURL& url) override;
   bool IsOmniboxExtensionURL(const std::string& url) override;
+  std::string GetExtensionControllingDSEPref() override;
 
   // history::HistoryServiceObserver:
   void OnURLVisited(history::HistoryService* history_service,
                     ui::PageTransition transition,
                     const history::URLRow& row,
                     const history::RedirectList& redirects,
                     base::Time visit_time) override;
 
  private:
   TemplateURLService* owner_;
   ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
       history_service_observer_;
   history::HistoryService* history_service_;
+  ExtensionPrefValueMap* extension_prefs_value_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeTemplateURLServiceClient);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_ENGINES_CHROME_TEMPLATE_URL_SERVICE_CLIENT_H_