Move Screen, its impls, DisplayObserver and DisplayChangeNotifier to ui/display

ui/display/display_finder.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 "ui/display/display_finder.h"
 
 #include <limits>
 
 #include "base/logging.h"
-#include "ui/gfx/display.h"
+#include "ui/display/display.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace display {
 
 const Display* FindDisplayNearestPoint(const std::vector<Display>& displays,
                                        const gfx::Point& point) {
   DCHECK(!displays.empty());
   int min_distance = std::numeric_limits<int>::max();
   const Display* nearest_display = nullptr;
@@ skipping 20 matching lines @@
     const int area = intersect.width() * intersect.height();
     if (area > max_area) {
       max_area = area;
       matching = &display;
     }
   }
   return matching;
 }
 
 }  // namespace display