Add field to monitor last visited time for each search engine

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 94 matching lines @@
     data->favicon_url = GURL(SubstituteInstallParam(
         *search_provider.favicon_url, install_parameter));
   }
   data->safe_for_autoreplace = false;
   if (search_provider.encoding) {
     data->input_encodings.clear();
     data->input_encodings.push_back(*search_provider.encoding);
   }
   data->date_created = base::Time();
   data->last_modified = base::Time();
+  data->last_visited = base::Time();

[Peter Kasting, 2016/11/21 03:35:07]

I don't really understand why |date_created| and |last_modified| were set to
Time() here, but you don't really need to fix those in this CL as that's
unrelated.

I think setting |last_visited| to Time() is correct, but should be done in the
constructor instead of here.  See comments there.

[ltian, 2016/11/28 22:08:01]

Done.

   data->prepopulate_id = 0;
   if (search_provider.alternate_urls) {
     data->alternate_urls.clear();
     for (size_t i = 0; i < search_provider.alternate_urls->size(); ++i) {
       if (!search_provider.alternate_urls->at(i).empty())
         data->alternate_urls.push_back(SubstituteInstallParam(
             search_provider.alternate_urls->at(i), install_parameter));
     }
   }
   return data;
@@ skipping 160 matching lines @@
 
 template <>
 void BrowserContextKeyedAPIFactory<
     SettingsOverridesAPI>::DeclareFactoryDependencies() {
   DependsOn(ExtensionPrefsFactory::GetInstance());
   DependsOn(PreferenceAPI::GetFactoryInstance());
   DependsOn(TemplateURLServiceFactory::GetInstance());
 }
 
 }  // namespace extensions