Support the removal of only session cookies or persistent cookies

chrome/common/extensions/api/webview_tag.json

 // 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.
 
 [
   {
     "namespace": "webviewTag",
     "description": "Use the <code>webview</code> tag to actively load live content from the web over the network and embed it in your Chrome App. Your app can control the appearance of the <code>webview</code> and interact with the web content, initiate navigations in an embedded web page, react to error events that happen within it, and more (see <a href=\"#usage\">Usage</a>).",
     "documentation_options": {
       "title": "<webview> Tag",
@@ skipping 14 matching lines @@
         }
       },
       {
         "id": "ClearDataTypeSet",
         "type": "object",
         "description": "A set of data types. Missing properties are interpreted as <code>false</code>.",
         "properties": {
           "appcache": { "type": "boolean", "optional": true, "description": "Websites' appcaches." },
           "cache": { "type": "boolean", "optional": true, "description": "Since Chrome 43.<br>The browser's cache. Note: when removing data, this clears the entire cache; it is not limited to the range you specify." },
           "cookies": { "type": "boolean", "optional": true, "description": "The partition's cookies." },
+          "sessionCookies": { "type": "boolean", "optional": true, "description": "The partition's session cookies." },
+          "persistentCookies": { "type": "boolean", "optional": true, "description": "The partition's persistent cookies." },
           "fileSystems": { "type": "boolean", "optional": true, "description": "Websites' filesystems." },
           "indexedDB": { "type": "boolean", "optional": true, "description": "Websites' IndexedDB data." },
           "localStorage": { "type": "boolean", "optional": true, "description": "Websites' local storage data." },
           "webSQL": { "type": "boolean", "optional": true, "description": "Websites' WebSQL data." }
         }
       },
       {
         "id": "ContextType",
         "type": "string",
         "enum": ["all", "page", "frame", "selection", "link", "editable", "image", "video", "audio"],
@@ skipping 1376 matching lines @@
         "$ref": "WebRequestEventInterface",
         "description": "Interface which provides access to webRequest events on the guest page."
       },
       "contextMenus": {
         "$ref": "ContextMenus",
         "description": "Similar to <a href='contextMenus'>chrome's ContextMenus API</a>, but applies to <code>webview</code> instead of browser. Use the <code>webview.contextMenus</code> API to add items to <code>webview</code>'s context menu. You can choose what types of objects your context menu additions apply to, such as images, hyperlinks, and pages."
       }
     }
   }
 ]