Write last_modified date to Content Settings in the PrefProvider

chrome/browser/content_settings/content_settings_internal_extension_provider.cc

 // Copyright (c) 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/content_settings/content_settings_internal_extension_provider.h"
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "chrome/browser/pdf/pdf_extension_util.h"
@@ skipping 194 matching lines @@
   ContentSettingsPattern secondary_pattern = ContentSettingsPattern::Wildcard();
   {
     base::AutoLock lock(lock_);
     if (setting == CONTENT_SETTING_DEFAULT) {
       value_map_.DeleteValue(primary_pattern,
                              secondary_pattern,
                              CONTENT_SETTINGS_TYPE_PLUGINS,
                              resource);
     } else {
       value_map_.SetValue(primary_pattern, secondary_pattern,
-                          CONTENT_SETTINGS_TYPE_PLUGINS, resource,
+                          CONTENT_SETTINGS_TYPE_PLUGINS, resource, base::Time(),

[msramek, 2017/04/19 10:49:15]

nit: Extension settings are processed when the extension is installed or at
browser startup; so I agree that a timestamp such as base::Time::Now() would be
meaningless here. But we should probably document it somewhere.

[dullweber, 2017/04/19 15:02:45]

I added a comment to show that this is done intentionally

                           new base::Value(setting));
     }
   }
   NotifyObservers(primary_pattern,
                   secondary_pattern,
                   CONTENT_SETTINGS_TYPE_PLUGINS,
                   resource);
 }
 
 }  // namespace content_settings