Add HiDPI flag for Windows

ui/base/ui_base_switches.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.
 
 // Defines all the command-line switches used by ui/base.
 
 #ifndef UI_BASE_UI_BASE_SWITCHES_H_
 #define UI_BASE_UI_BASE_SWITCHES_H_
 
 #include "base/compiler_specific.h"
 #include "ui/base/ui_export.h"
 
 namespace switches {
 
 UI_EXPORT extern const char kDisableDwmComposition[];
 UI_EXPORT extern const char kDisableNewDialogStyle[];
 UI_EXPORT extern const char kDisableTouchAdjustment[];
 UI_EXPORT extern const char kDisableTouchDragDrop[];
 UI_EXPORT extern const char kDisableTouchEditing[];
 UI_EXPORT extern const char kDisableViewsTextfield[];
 UI_EXPORT extern const char kEnableBezelTouch[];
 UI_EXPORT extern const char kEnableNewDialogStyle[];
 UI_EXPORT extern const char kEnableTouchDragDrop[];
 UI_EXPORT extern const char kEnableTouchEditing[];
 UI_EXPORT extern const char kEnableViewsTextfield[];
 UI_EXPORT extern const char kForceDeviceScaleFactor[];
+UI_EXPORT extern const char kHighDPISupport[];
 UI_EXPORT extern const char kHighlightMissingScaledResources[];
 UI_EXPORT extern const char kLang[];
 UI_EXPORT extern const char kLocalePak[];
 UI_EXPORT extern const char kNoMessageBox[];
 UI_EXPORT extern const char kTouchEvents[];
 UI_EXPORT extern const char kTouchEventsAuto[];
 UI_EXPORT extern const char kTouchEventsDisabled[];
 UI_EXPORT extern const char kTouchEventsEnabled[];
 UI_EXPORT extern const char kTouchOptimizedUI[];
 UI_EXPORT extern const char kTouchOptimizedUIAuto[];
@@ skipping 11 matching lines @@
 UI_EXPORT extern const char kDisableCoreAnimationPlugins[];
 #endif
 
 #if defined(TOOLKIT_VIEWS) && defined(OS_LINUX)
 UI_EXPORT extern const char kTouchDevices[];
 #endif
 
 }  // namespace switches
 
 #endif  // UI_BASE_UI_BASE_SWITCHES_H_