Start to decouple display::Display from ws::PlatformDisplay.

services/ui/display/screen_manager_delegate.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_DISPLAY_SCREEN_MANAGER_DELEGATE_H_
 #define SERVICES_UI_DISPLAY_SCREEN_MANAGER_DELEGATE_H_
 
 #include <stdint.h>
 
 namespace display {
 
+class Display;
 struct ViewportMetrics;
 
 // The ScreenManagerDelegate will be informed of changes to the display or
 // screen state by ScreenManager.
 class ScreenManagerDelegate {
  public:
-  // Called when a display is added. |id| is the display id of the new display
-  // and |metrics| contains display viewport information.
-  virtual void OnDisplayAdded(int64_t id, const ViewportMetrics& metrics) = 0;
+  // Called when a display is added.
+  virtual void OnDisplayAdded(const display::Display& display,
+                              const ViewportMetrics& metrics) = 0;
 
-  // Called when a display is removed. |id| is the display id of the display
-  // that was removed.
-  virtual void OnDisplayRemoved(int64_t id) = 0;
+  // Called when a display is modified.
+  virtual void OnDisplayModified(const display::Display& display,
+                                 const ViewportMetrics& metrics) = 0;
 
-  // Called when a display is modified. |id| is the display id of the modified
-  // display and |metrics| contains updated display viewport information.
-  virtual void OnDisplayModified(int64_t id,
-                                 const ViewportMetrics& metrics) = 0;
+  // Called when a display is removed.
+  virtual void OnDisplayRemoved(int64_t display_id) = 0;
 
   // Called when the primary display is changed.
   virtual void OnPrimaryDisplayChanged(int64_t primary_display_id) = 0;
 
  protected:
   virtual ~ScreenManagerDelegate() {}
 };
 
 }  // namespace display
 
 #endif  // SERVICES_UI_DISPLAY_SCREEN_MANAGER_DELEGATE_H_