Allow component IME extension use app.window and add 'ime' window type for app window

extensions/common/api/app_window.idl

 // 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.
 
 // Use the <code>chrome.app.window</code> API to create windows. Windows
 // have an optional frame with title bar and size controls. They are not
 // associated with any Chrome browser windows. See the <a
 // href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/samples/window-state">
 // Window State Sample</a> for a demonstration of these options.
 namespace app.window {
@@ skipping 197 matching lines @@
 
     // Maximum width of the window.
     [deprecated="Use innerBounds or outerBounds."] long? maxWidth;
 
     // Maximum height of the window.
     [deprecated="Use innerBounds or outerBounds."] long? maxHeight;
 
     // Type of window to create.
     [nodoc] WindowType? type;
 
+    // Creates a special ime window. This window is not focusable and can be
+    // stacked above virtual keyboard window. This is restriced to component ime
+    // extensions.
+    // Requires app.window.ime API permission.
+    [nodoc] boolean? ime;
+
     // Frame type: <code>none</code> or <code>chrome</code> (defaults to
     // <code>chrome</code>). For <code>none</code>, the
     // <code>-webkit-app-region</code> CSS property can be used to apply
     // draggability to the app's window. <code>-webkit-app-region: drag</code>
     // can be used to mark regions draggable. <code>no-drag</code> can be used
     // to disable this style on nested elements.
     //
     // Use of <code>FrameOptions</code> is new in M36.
     (DOMString or FrameOptions)? frame;
 
@@ skipping 236 matching lines @@
     // Fired when the window is restored from being minimized or maximized.
     [nocompile] static void onRestored();
 
     // Fired when the window's ability to use alpha transparency changes.
     [nocompile, nodoc] static void onAlphaEnabledChanged();
 
     // Event for testing. Lets tests wait until a window has been shown.
     [nocompile, nodoc] static void onWindowFirstShown();
   };
 };