Tabs Extension: Implementation of tabs.duplicate api.

chrome/common/extensions/api/tabs.json

 // Copyright (c) 2012 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": "tabs",
     "dependencies": [ "extension", "windows" ],
     "types": [
       {
@@ skipping 256 matching lines @@
               {
                 "name": "tab",
                 "$ref": "Tab",
                 "description": "Details about the created tab. Will contain the ID of the new tab."
               }
             ]
           }
         ]
       },
       {
+        "name": "duplicate",
+        "type": "function",
+        "description": "Duplicates a tab. Note: This function can be used without requesting the 'tabs' permission in the manifest.",
+        "parameters": [
+          {
+            "type": "integer",
+            "name": "tabId",
+            "minimum": 0,
+            "description": "The ID of the tab which is to be duplicated."
+          },
+          {
+            "type": "function",
+            "name": "callback",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "tab",
+                "optional": true,
+                "description": "Details about the duplicated tab. The Tab object doesn't contain url, title and faviconUrl if the 'tabs' permission has not been requested.",
+                "$ref": "Tab"
+              }
+            ]
+          }
+        ]
+      },
+      {
         "name": "query",
         "type": "function",
         "description": "Gets all tabs that have the specified properties, or all tabs if no properties are specified.",
         "parameters": [
           {
             "type": "object",
             "name": "queryInfo",
             "properties": {
               "active": {
                 "type": "boolean",
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             "name": "removeInfo",
             "properties": {
               "isWindowClosing": {"type": "boolean", "description": "True when the tab is being closed because its window is being closed." }
             }
           }
         ]
       }
     ]
   }
 ]