mus: Changes SetDisplayRoot() to create actual display

services/ui/ws/display_manager.h

 // Copyright 2016 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 SERVICES_UI_WS_DISPLAY_MANAGER_H_
 #define SERVICES_UI_WS_DISPLAY_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 29 matching lines @@
   // Returns the UserDisplayManager for |user_id|. DisplayManager owns the
   // return value.
   UserDisplayManager* GetUserDisplayManager(const UserId& user_id);
 
   // Returns the CursorLocationManager for |user_id|.
   CursorLocationManager* GetCursorLocationManager(const UserId& user_id);
 
   // Adds/removes a Display. DisplayManager owns the Displays.
   // TODO(sky): make add take a scoped_ptr.
   void AddDisplay(Display* display);
+  // Called when the window manager explicitly adds a new display.
+  void AddDisplayForWindowManager(const display::Display& display,
+                                  const display::ViewportMetrics& metrics);
   void DestroyDisplay(Display* display);
   void DestroyAllDisplays();
   const std::set<Display*>& displays() { return displays_; }
   std::set<const Display*> displays() const;
 
   // Notifies when something about the Display changes.
   void OnDisplayUpdate(const display::Display& display);
 
   // Returns the Display that contains |window|, or null if |window| is not
   // attached to a display.
@@ skipping 57 matching lines @@
   // ID to use for next root node.
   ClientSpecificId next_root_id_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_DISPLAY_MANAGER_H_