Revert of Remove some ifdefs from ash since it only supports ChromeOS now.

ash/display/display_util.h

 // Copyright 2014 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 ASH_DISPLAY_DISPLAY_UTIL_H_
 #define ASH_DISPLAY_DISPLAY_UTIL_H_
 
 #include <memory>
 
+#include "ash/ash_export.h"
 #include "base/strings/string16.h"
 
 namespace aura {
 class Window;
 }
 
 namespace display {
 class DisplayManager;
 }
 
 namespace gfx {
 class Point;
 class Rect;
 }
 
 namespace ash {
 class AshWindowTreeHost;
 class MouseWarpController;
 
 // Creates a MouseWarpController for the current display
 // configuration. |drag_source| is the window where dragging
 // started, or nullptr otherwise.
 std::unique_ptr<MouseWarpController> CreateMouseWarpController(
     display::DisplayManager* manager,
     aura::Window* drag_source);
 
 // Creates edge bounds from |bounds_in_screen| that fits the edge
 // of the native window for |ash_host|.
-gfx::Rect GetNativeEdgeBounds(AshWindowTreeHost* ash_host,
-                              const gfx::Rect& bounds_in_screen);
+ASH_EXPORT gfx::Rect GetNativeEdgeBounds(AshWindowTreeHost* ash_host,
+                                         const gfx::Rect& bounds_in_screen);
 
 // Moves the cursor to the point inside the |ash_host| that is closest to
 // the point_in_screen, which may be outside of the root window.
 // |update_last_loation_now| is used for the test to update the mouse
 // location synchronously.
 void MoveCursorTo(AshWindowTreeHost* ash_host,
                   const gfx::Point& point_in_screen,
                   bool update_last_location_now);
 
+#if defined(OS_CHROMEOS)
 // Shows the notification message for display related issues, and optionally
 // adds a button to send a feedback report.
 void ShowDisplayErrorNotification(const base::string16& message,
                                   bool allow_feedback);
+#endif
 
-base::string16 GetDisplayErrorNotificationMessageForTest();
+ASH_EXPORT base::string16 GetDisplayErrorNotificationMessageForTest();
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_DISPLAY_UTIL_H_