Make extensions DSE persistent in browser prefs

chrome/browser/extensions/api/settings_overrides/settings_overrides_api.cc

 // Copyright 2013 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/extensions/api/settings_overrides/settings_overrides_api.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/lazy_instance.h"
@@ skipping 218 matching lines @@
   if (settings) {
     if (settings->homepage) {
       UnsetPref(extension->id(), prefs::kHomePage);
       UnsetPref(extension->id(), prefs::kHomePageIsNewTabPage);
     }
     if (!settings->startup_pages.empty()) {
       UnsetPref(extension->id(), prefs::kRestoreOnStartup);
       UnsetPref(extension->id(), prefs::kURLsToRestoreOnStartup);
     }
     if (settings->search_engine) {
+      if (settings->search_engine->is_default) {
+        // Current extension can be overriding DSE.
+        UnsetPref(extension->id(),
+                  DefaultSearchManager::kDefaultSearchProviderDataPrefName);
+      }
       DCHECK(url_service_);
       if (url_service_->loaded()) {
         url_service_->RemoveExtensionControlledTURL(
             extension->id(), TemplateURL::NORMAL_CONTROLLED_BY_EXTENSION);
       } else {
         pending_extensions_.erase(extension);
       }
     }
   }
 }
@@ skipping 37 matching lines @@
 
 template <>
 void BrowserContextKeyedAPIFactory<
     SettingsOverridesAPI>::DeclareFactoryDependencies() {
   DependsOn(ExtensionPrefsFactory::GetInstance());
   DependsOn(PreferenceAPI::GetFactoryInstance());
   DependsOn(TemplateURLServiceFactory::GetInstance());
 }
 
 }  // namespace extensions