Changes how window manager obtains WindowTree from mus

components/mus/public/cpp/window_manager_delegate.h

 // 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.
 
 #ifndef COMPONENTS_MUS_PUBLIC_CPP_WINDOW_MANAGER_DELEGATE_H_
 #define COMPONENTS_MUS_PUBLIC_CPP_WINDOW_MANAGER_DELEGATE_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "components/mus/public/interfaces/cursor.mojom.h"
 #include "components/mus/public/interfaces/event_matcher.mojom.h"
 #include "components/mus/public/interfaces/window_manager_constants.mojom.h"
 #include "ui/events/mojo/event.mojom.h"
 
+namespace display {
+class Display;
+}
+
 namespace gfx {
 class Insets;
 class Rect;
 class Vector2d;
 }
 
 namespace ui {
 class Event;
 }
 
@@ skipping 58 matching lines @@
   // of OnWmCreateTopLevelWindow().
   virtual Window* OnWmCreateTopLevelWindow(
       std::map<std::string, std::vector<uint8_t>>* properties) = 0;
 
   // Called when a Mus client's jankiness changes. |windows| is the set of
   // windows owned by the window manager in which the client is embedded.
   virtual void OnWmClientJankinessChanged(
       const std::set<Window*>& client_windows,
       bool janky) = 0;
 
+  // Called when a display is added. |window| is the root of the window tree for
+  // the specified display.
+  virtual void OnWmNewDisplay(Window* window,
+                              const display::Display& display) = 0;
+
   virtual void OnAccelerator(uint32_t id, const ui::Event& event) = 0;
 
  protected:
   virtual ~WindowManagerDelegate() {}
 };
 
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_PUBLIC_CPP_WINDOW_MANAGER_DELEGATE_H_