Change ui cursor identifiers to an enum class.

ui/gfx/native_widget_types.h

 // Copyright (c) 2012 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 UI_GFX_NATIVE_WIDGET_TYPES_H_
 #define UI_GFX_NATIVE_WIDGET_TYPES_H_
 
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 28 matching lines @@
 // The name 'View' here meshes with OS X where the UI elements are called
 // 'views' and with our Chrome UI code where the elements are also called
 // 'views'.
 
 #if defined(USE_AURA)
 namespace aura {
 class Window;
 }
 namespace ui {
 class Cursor;
+enum class CursorType;
 class Event;
 }
 #endif  // defined(USE_AURA)
 
 #if defined(OS_WIN)
 #include <windows.h>  // NOLINT
 typedef struct HFONT__* HFONT;
 struct IAccessible;
 #elif defined(OS_IOS)
 struct CGContext;
@@ skipping 90 matching lines @@
 // Linux doesn't have a native font type.
 #if defined(USE_X11) && !defined(OS_CHROMEOS)
 typedef AtkObject* NativeViewAccessible;
 #else
 typedef void* NativeViewAccessible;
 #endif
 #endif
 
 // A constant value to indicate that gfx::NativeCursor refers to no cursor.
 #if defined(USE_AURA)
-const int kNullCursor = 0;
+const ui::CursorType kNullCursor = static_cast<ui::CursorType>(0);
 #else
 const gfx::NativeCursor kNullCursor = static_cast<gfx::NativeCursor>(NULL);
 #endif
 
 #if defined(OS_IOS)
 typedef UIImage NativeImageType;
 #elif defined(OS_MACOSX)
 typedef NSImage NativeImageType;
 #else
 typedef SkBitmap NativeImageType;
@@ skipping 26 matching lines @@
 #elif defined(USE_OZONE)
 typedef int32_t AcceleratedWidget;
 constexpr AcceleratedWidget kNullAcceleratedWidget = 0;
 #else
 #error unknown platform
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_NATIVE_WIDGET_TYPES_H_