Restructure public side of window_manager service

mojo/services/window_manager/public/interfaces/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.
 
 module mojo;
 
 import "mojo/services/public/interfaces/geometry/geometry.mojom";
 import "mojo/services/public/interfaces/input_events/input_events.mojom";
 
 // WindowManagerInternal is an interface provided by the WindowManager
@@ skipping 17 matching lines @@
   // Sets the native viewport size.
   SetViewportSize(mojo.Size size);
 
   // Clones the tree rooted at |view_id|. When the animation completes the clone
   // is destroyed.
   // TODO(sky): add actual animation.
   // TODO(sky): I think this only makes sense when destroying (view is
   // already visible), should it be named to indicate this?
   CloneAndAnimate(uint32 view_id);
 };