NOT YET READY: Making chrome.windows.create establish an actual "opener" relationship.

chrome/common/extensions/api/windows.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": "windows",
     "description": "Use the <code>chrome.windows</code> API to interact with browser windows. You can use this API to create, modify, and rearrange windows in the browser.",
     "compiler_options": {
       "implemented_in": "chrome/browser/extensions/api/tabs/tabs_api.h"
@@ skipping 206 matching lines @@
               "incognito": {"type": "boolean", "optional": true, "description": "Whether the new window should be an incognito window."},
               "type": {
                 "$ref": "CreateType",
                 "optional": true,
                 "description": "Specifies what type of browser window to create."
               },
               "state": {
                 "$ref": "WindowState",
                 "optional": true,
                 "description": "The initial state of the window. The 'minimized', 'maximized' and 'fullscreen' states cannot be combined with 'left', 'top', 'width' or 'height'."
-              }
+              },
+              "setSelfAsOpener": {"type": "boolean", "optional": true, "description": "Whether the newly opened window will be in the same unit of related browsing contexts [1], having its window.opener set to the caller and otherwise behaving similarily to window.open.  [1] - https://www.w3.org/TR/html51/browsers.html#unit-of-related-browsing-contexts"}
             },
             "optional": true
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
             "parameters": [
               {
                 "name": "window", "$ref": "Window", "description": "Contains details about the created window.",
@@ skipping 97 matching lines @@
             "description": "Conditions that the window's type being removed must satisfy. By default it will satisfy <code>['app', 'normal', 'panel', 'popup']</code>, with <code>'app'</code> and <code>'panel'</code> window types limited to the extension's own windows."
           }
         ],
         "parameters": [
           {"type": "integer", "name": "windowId", "minimum": -1, "description": "ID of the newly focused window."}
         ]
       }
     ]
   }
 ]