mash: Reverse the responsibilities of the NewWindowClient.

ash/public/interfaces/new_window.mojom

 // Copyright 2016 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.
 
 module ash.mojom;
 
-// A delegate interface delegate to create or open windows that are not part of
-// ash.
+// An exported object in ash which lets an ash consumer set a client interface.
+interface NewWindowController {
+  SetClient(associated NewWindowClient client);
+};
+
+// A delegate interface that an ash user sends to ash to handle certain window
+// management responsibilities.
 interface NewWindowClient {
   // Invoked when the user uses Ctrl+T to open a new tab.
   NewTab();
 
   // Invoked when the user uses Ctrl-N or Ctrl-Shift-N to open a new window.
   NewWindow(bool incognito);
 
   // Invoked when an accelerator is used to open the file manager.
   OpenFileManager();
 
   // Invoked when the user opens Crosh.
   OpenCrosh();
 
   // Invoked when an accelerator is used to open help center.
   OpenGetHelp();
 
   // Invoked when the user uses Shift+Ctrl+T to restore the closed tab.
   RestoreTab();
 
   // Shows the keyboard shortcut overlay.
   ShowKeyboardOverlay();
 
   // Shows the task manager window.
   ShowTaskManager();
 
   // Opens the feedback page for "Report Issue".
   OpenFeedbackPage();
 };