Remove unnecessary display:: namespaces.

ui/display/test/test_screen.cc

 // Copyright 2015 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 <vector>
 
 #include "ui/display/test/test_screen.h"
 
 namespace display {
 namespace test {
 
 TestScreen::TestScreen() {
-  display::Display display;
+  Display display;
   ProcessDisplayChanged(display, true /* is_primary */);
 }
 
 TestScreen::~TestScreen() {}
 
 gfx::Point TestScreen::GetCursorScreenPoint() {
   return gfx::Point();
 }
 
 bool TestScreen::IsWindowUnderCursor(gfx::NativeWindow window) {
   return false;
 }
 
 gfx::NativeWindow TestScreen::GetWindowAtScreenPoint(const gfx::Point& point) {
   return nullptr;
 }
 
 Display TestScreen::GetDisplayNearestWindow(gfx::NativeView view) const {
   return GetPrimaryDisplay();
 }
 
 }  // namespace test
 }  // namespace display