Return AltGraph for right-Alt keydown/keyup, under layouts which use AltGraph.

ui/events/keycodes/platform_key_map_win.h

 // Copyright (c) 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.
 
 #ifndef UI_EVENTS_KEYCODES_PLATFORM_KEY_MAP_WIN_H_
 #define UI_EVENTS_KEYCODES_PLATFORM_KEY_MAP_WIN_H_
 
 #include <windows.h>
 
 #include <unordered_map>
@@ skipping 26 matching lines @@
   // TODO(chongz): Expose this function when we need to access separate layout.
   // Returns the DomKey 'meaning' of |KeyboardCode| in the context of specified
   // |EventFlags| and stored keyboard layout.
   DomKey DomKeyFromKeyboardCodeImpl(KeyboardCode, int flags) const;
 
   // TODO(chongz): Expose this function in response to WM_INPUTLANGCHANGE.
   void UpdateLayout(HKL layout);
 
   HKL keyboard_layout_ = 0;
 
+  // True if |keyboard_layout_| makes use of the AltGraph modifier.
+  bool has_alt_graph_ = false;
+
   typedef std::pair<int /*KeyboardCode*/, int /*EventFlags*/>
       KeyboardCodeEventFlagsPair;
   typedef std::unordered_map<KeyboardCodeEventFlagsPair,
                              DomKey,
                              base::IntPairHash<std::pair<int, int>>>
       KeyboardCodeToKeyMap;
   KeyboardCodeToKeyMap printable_keycode_to_key_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformKeyMap);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_KEYCODES_PLATFORM_KEY_MAP_WIN_H_