Remove docked windows entirely in M59.

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"
     },
     "types": [
       {
         "id": "WindowType",
         "type": "string",
         "description": "The type of browser window this is. Under some circumstances a Window may not be assigned type property, for example when querying closed windows from the $(ref:sessions) API.",
         "enum": ["normal", "popup", "panel", "app", "devtools"]
       },
       {
         "id": "WindowState",
         "type": "string",
         "description": "The state of this browser window. Under some circumstances a Window may not be assigned state property, for example when querying closed windows from the $(ref:sessions) API.",
-        "enum": ["normal", "minimized", "maximized", "fullscreen", "docked"]

[afakhry, 2017/03/09 22:28:27]

I wonder if this change will break some extensions?

+        "enum": ["normal", "minimized", "maximized", "fullscreen"]
       },
       {
         "id": "Window",
         "type": "object",
         "properties": {
           "id": {"type": "integer", "optional": true, "minimum": 0, "description": "The ID of the window. Window IDs are unique within a browser session. Under some circumstances a Window may not be assigned an ID, for example when querying windows using the $(ref:sessions) API, in which case a session ID may be present."},
           "focused": {"type": "boolean", "description": "Whether the window is currently the focused window."},
           "top": {"type": "integer", "optional": true, "description": "The offset of the window from the top edge of the screen in pixels. Under some circumstances a Window may not be assigned top property, for example when querying closed windows from the $(ref:sessions) API."},
           "left": {"type": "integer", "optional": true, "description": "The offset of the window from the left edge of the screen in pixels. Under some circumstances a Window may not be assigned left property, for example when querying closed windows from the $(ref:sessions) API."},
           "width": {"type": "integer", "optional": true, "description": "The width of the window, including the frame, in pixels. Under some circumstances a Window may not be assigned width property, for example when querying closed windows from the $(ref:sessions) API."},
@@ skipping 281 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."}
         ]
       }
     ]
   }
 ]