[ozone/wayland] Implement basic keyboard handling support

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.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 UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_LAYOUT_ENGINE_H_
 #define UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_LAYOUT_ENGINE_H_
 
 #include <stdint.h>
 #include <xkbcommon/xkbcommon.h>
 
@@ skipping 54 matching lines @@
   // accounting for non-US layouts. May return VKEY_UNKNOWN, in which case the
   // caller should, as a last resort, obtain a KeyboardCode using
   // |DomCodeToUsLayoutDomKey()|.
   KeyboardCode DifficultKeyboardCode(DomCode dom_code,
                                      int ui_flags,
                                      xkb_keycode_t xkb_keycode,
                                      xkb_mod_mask_t xkb_flags,
                                      xkb_keysym_t xkb_keysym,
                                      base::char16 character) const;
 
+  // Sets a new XKB keymap. This updates xkb_state_ (which takes ownership
+  // of the keymap), and updates xkb_flag_map_ for the new keymap.
+  virtual void SetKeymap(xkb_keymap* keymap);
+
   // Maps DomCode to xkb_keycode_t.
   const XkbKeyCodeConverter& key_code_converter_;
 
+  // libxkbcommon uses explicit reference counting for its structures,
+  // so we need to trigger its cleanup.
+  std::unique_ptr<xkb_state, XkbStateDeleter> xkb_state_;
+
  private:
   struct XkbKeymapEntry {
     std::string layout_name;
     xkb_keymap* keymap;
   };
   std::vector<XkbKeymapEntry> xkb_keymaps_;
-  // Sets a new XKB keymap. This updates xkb_state_ (which takes ownership
-  // of the keymap), and updates xkb_flag_map_ for the new keymap.
-  void SetKeymap(xkb_keymap* keymap);
 
   // Returns the XKB modifiers flags corresponding to the given EventFlags.
   xkb_mod_mask_t EventFlagsToXkbFlags(int ui_flags) const;
 
   // Determines the XKB KeySym and character associated with a key.
   // Returns true on success. This is virtual for testing.
   virtual bool XkbLookup(xkb_keycode_t xkb_keycode,
                          xkb_mod_mask_t xkb_flags,
                          xkb_keysym_t* xkb_keysym,
                          uint32_t* character) const;
 
   // Helper for difficult VKEY lookup. If |ui_flags| matches |base_flags|,
   // returns |base_character|; otherwise returns the XKB character for
   // the keycode and mapped |ui_flags|.
   base::char16 XkbSubCharacter(xkb_keycode_t xkb_keycode,
                                xkb_mod_mask_t base_flags,
                                base::char16 base_character,
                                int ui_flags) const;
 
   // Callback when keymap file is loaded complete.
   void OnKeymapLoaded(const std::string& layout_name,
                       std::unique_ptr<char, base::FreeDeleter> keymap_str);
 
-  // libxkbcommon uses explicit reference counting for its structures,
-  // so we need to trigger its cleanup.
   std::unique_ptr<xkb_context, XkbContextDeleter> xkb_context_;
-  std::unique_ptr<xkb_state, XkbStateDeleter> xkb_state_;
 
   std::string current_layout_name_;
 
   // Support weak pointers for attach & detach callbacks.
   base::WeakPtrFactory<XkbKeyboardLayoutEngine> weak_ptr_factory_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_LAYOUT_ENGINE_H_