Add 'autoplay' content settings and expose it to Blink.

components/content_settings/core/browser/content_settings_registry.cc

 // Copyright 2015 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 "components/content_settings/core/browser/content_settings_registry.h"
 
 #include <utility>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 253 matching lines @@
            WebsiteSettingsInfo::REQUESTING_ORIGIN_ONLY_SCOPE,
            ContentSettingsInfo::INHERIT_IN_INCOGNITO);
 
   Register(CONTENT_SETTINGS_TYPE_BACKGROUND_SYNC, "background-sync",
            CONTENT_SETTING_ALLOW, WebsiteSettingsInfo::UNSYNCABLE,
            WhitelistedSchemes(),
            ValidSettings(CONTENT_SETTING_ALLOW, CONTENT_SETTING_BLOCK),
            WebsiteSettingsInfo::REQUESTING_ORIGIN_ONLY_SCOPE,
            ContentSettingsInfo::INHERIT_IN_INCOGNITO);
 
+  Register(CONTENT_SETTINGS_TYPE_AUTOPLAY, "autoplay",
+           CONTENT_SETTING_ALLOW, WebsiteSettingsInfo::UNSYNCABLE,
+           WhitelistedSchemes(),
+           ValidSettings(CONTENT_SETTING_ALLOW, CONTENT_SETTING_BLOCK),
+           WebsiteSettingsInfo::REQUESTING_ORIGIN_ONLY_SCOPE,
+           ContentSettingsInfo::INHERIT_IN_INCOGNITO);
+
   // Content settings that aren't used to store any data. TODO(raymes): use a
   // different mechanism rather than content settings to represent these.
   // Since nothing is stored in them, there is no real point in them being a
   // content setting.
   Register(CONTENT_SETTINGS_TYPE_PROTOCOL_HANDLERS, "protocol-handler",
            CONTENT_SETTING_DEFAULT, WebsiteSettingsInfo::UNSYNCABLE,
            WhitelistedSchemes(), ValidSettings(),
            WebsiteSettingsInfo::TOP_LEVEL_DOMAIN_ONLY_SCOPE,
            ContentSettingsInfo::INHERIT_IN_INCOGNITO);
 
@@ skipping 34 matching lines @@
           type, name, std::move(default_value), sync_status,
           WebsiteSettingsInfo::NOT_LOSSY, scoping_type,
           WebsiteSettingsInfo::INHERIT_IN_INCOGNITO);
   DCHECK(!ContainsKey(content_settings_info_, type));
   content_settings_info_[type] = make_scoped_ptr(
       new ContentSettingsInfo(website_settings_info, whitelisted_schemes,
                               valid_settings, incognito_behavior));
 }
 
 }  // namespace content_settings