Primary display change notifications.

services/ui/display/platform_screen_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_PLATFORM_SCREEN_DELEGATE_H_
 #define SERVICES_UI_DISPLAY_PLATFORM_SCREEN_DELEGATE_H_
 
 #include <stdint.h>
 
 namespace gfx {
@@ skipping 16 matching lines @@
 
   // 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. |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 the primary display is changed.
+  virtual void OnPrimaryDisplayChanged(int64_t primary_display_id) = 0;
+
  protected:
   virtual ~PlatformScreenDelegate() {}
 };
 
 }  // namespace display
 
 #endif  // SERVICES_UI_DISPLAY_PLATFORM_SCREEN_DELEGATE_H_