Add PlatformScreenDelegate and start implementation.

services/ui/ws/user_display_manager.cc

 // 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.
 
 #include "services/ui/ws/user_display_manager.h"
 
 #include <utility>
 
 #include "services/ui/ws/display.h"
 #include "services/ui/ws/display_manager.h"
-#include "services/ui/ws/display_manager_delegate.h"
+#include "services/ui/ws/user_display_manager_delegate.h"
 
 namespace ui {
 namespace ws {
 
 UserDisplayManager::UserDisplayManager(ws::DisplayManager* display_manager,
-                                       DisplayManagerDelegate* delegate,
+                                       UserDisplayManagerDelegate* delegate,
                                        const UserId& user_id)
     : display_manager_(display_manager),
       delegate_(delegate),
       user_id_(user_id),
       got_valid_frame_decorations_(
           delegate->GetFrameDecorationsForUser(user_id, nullptr)),
       current_cursor_location_(0) {}
 
 UserDisplayManager::~UserDisplayManager() {}
 
@@ skipping 116 matching lines @@
 
 void UserDisplayManager::AddObserver(
     mojom::DisplayManagerObserverPtr observer) {
   mojom::DisplayManagerObserver* observer_impl = observer.get();
   display_manager_observers_.AddPtr(std::move(observer));
   OnObserverAdded(observer_impl);
 }
 
 }  // namespace ws
 }  // namespace ui