Makes windowmanager draw non-client area

components/mus/public/interfaces/window_manager.mojom

 // Copyright 2015 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 mus.mojom;
 
 import "components/mus/public/interfaces/window_manager_constants.mojom";
 import "components/mus/public/interfaces/window_tree.mojom";
 import "ui/mojo/geometry/geometry.mojom";
 
+struct WindowManagerConfig {
+  array<Display> displays;
+  mojo.Insets normal_client_area_insets;
+  mojo.Insets maximized_client_area_insets;
+};
+
 // Represents a core interface that should be implemented by any window manager
 // built on top of Mus.
 // For security reasons, methods that take window_ids can only pass window ids
 // created by calls to OpenWindow() from the *same connection* to the window
 // manager. The callback indicates success or failure.
 interface WindowManager {
   // The window bounds as set by user input. Type: gfx::Rect.
   const string kUserSetBounds_Property = "prop:user-set-bounds";
   // The window's preferred size as defined by its content. Type: gfx::Size.
   const string kPreferredSize_Property = "prop:preferred-size";
   // The window's show state. Type: ShowState.
   const string kShowState_Property = "prop:show-state";
 
   OpenWindow(WindowTreeClient client,
              map<string, array<uint8>> properties);
 
   // Updates the window's preferred size and triggers a relayout of the window
   // within its container.
   SetPreferredSize(uint32 window_id, mojo.Size size) =>
       (WindowManagerErrorCode result);
 
   SetBounds(uint32 window_id, mojo.Rect bounds) =>
       (WindowManagerErrorCode result);
 
   SetShowState(uint32 window_id, ShowState show_state) =>
       (WindowManagerErrorCode result);
 
-  GetDisplays() => (array<Display> displays);
+  GetConfig() => (WindowManagerConfig config);
 };