Make it possible to change the viewport size

mojo/services/public/interfaces/window_manager/window_manager_internal.mojom

 // 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.
 
+import "mojo/services/public/interfaces/geometry/geometry.mojom";
 import "mojo/services/public/interfaces/input_events/input_events.mojom";
 
 module mojo {
 
 // ViewManager provides this interface to the WindowManager. It enables
 // capabilities specific to the WindowManager.
 interface WindowManagerInternalClient {
   // Dispatches the specified input event to the specified view.
   DispatchInputEventToView(uint32 view_id, mojo.Event event);
+
+  // Sets the native viewport size.
+  SetViewportSize(mojo.Size size);
 };
 
 }