WIP: simplified display management in ash

ui/aura/mus/window_tree_host_mus_init_params.h

 // Copyright 2017 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.
 
 #ifndef UI_AURA_MUS_WINDOW_TREE_HOST_MUS_INIT_PARAMS_H_
 #define UI_AURA_MUS_WINDOW_TREE_HOST_MUS_INIT_PARAMS_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "cc/surfaces/frame_sink_id.h"
+#include "services/ui/public/interfaces/window_manager_constants.mojom.h"
 #include "ui/aura/aura_export.h"
 
+namespace display {
+class Display;
+}
+
 namespace aura {
 
 class WindowPortMus;
 class WindowTreeClient;
 
 // Used to create a WindowTreeHostMus. The typical case is to use
 // CreateInitParamsForTopLevel().
 struct AURA_EXPORT WindowTreeHostMusInitParams {
   WindowTreeHostMusInitParams();
   WindowTreeHostMusInitParams(WindowTreeHostMusInitParams&& other);
   ~WindowTreeHostMusInitParams();
 
   // The WindowTreeClient; must be specified.
   WindowTreeClient* window_tree_client = nullptr;
 
   // Used to create the Window; must be specified.
   std::unique_ptr<WindowPortMus> window_port;
 
   // Properties to send to the server as well as to set on the Window.
   std::map<std::string, std::vector<uint8_t>> properties;
 
   cc::FrameSinkId frame_sink_id;
 
   // Id of the display the window should be created on.
   int64_t display_id = 0;
+
+  // Only used when creating a WindowTreeHostMus for a display.
+  std::unique_ptr<display::Display> display;
+
+  // Only used when creating a WindowTreeHostMus in the window manager.
+  ui::mojom::WmViewportMetrics viewport_metrics;
 };
 
 // Creates a WindowTreeHostMusInitParams that is used when creating a top-level
 // window.
 AURA_EXPORT WindowTreeHostMusInitParams CreateInitParamsForTopLevel(
     WindowTreeClient* window_tree_client,
     std::map<std::string, std::vector<uint8_t>> properties =
         std::map<std::string, std::vector<uint8_t>>());
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_TREE_HOST_MUS_INIT_PARAMS_H_