Remove app_shell chrome.shell API and ShellAppWindow

extensions/shell/common/api/shell.idl

-// Copyright 2014 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.
-
-// Use the <code>chrome.shell</code> API to create windows. The
-// <code>createWindow</code> API is a subset of
-// <code>chrome.app.window.create</code>.
-namespace shell {
-
-  // Called in the creating window (parent) before the load event is called in
-  // the created window (child). The parent can set fields or functions on the
-  // child usable from onload. E.g. background.js:<br>
-  // <code>function(createdWindow) { createdWindow.contentWindow.foo =
-  // function () { }; };</code>
-  // <br>window.js:<br>
-  // <code>window.onload = function () { foo(); }</code>
-  callback CreateWindowCallback =
-      void ([instanceOf=AppWindow] object createdWindow);
-
-  [noinline_doc] dictionary AppWindow {
-    // The JavaScript 'window' object for the created child.
-    [instanceOf=Window] object contentWindow;
-  };
-
-  interface Functions {
-    // Creates a fullscreen window on the default display. Options are ignored.
-    static void createWindow(DOMString url,
-                             optional object optionsPlaceholder,
-                             optional CreateWindowCallback callback);
-
-    // Returns an $(ref:AppWindow) object for the current script context
-    // (i.e. JavaScript 'window' object).
-    [nocompile] static AppWindow currentWindow();
-    [nocompile, nodoc] static void initializeAppWindow();
-  };
-};