[ozone/wayland] Implement basic keyboard handling support

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc

 // 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.
 
 #include "ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h"
 
 #include <stddef.h>
 #include <xkbcommon/xkbcommon-names.h>
 
 #include <algorithm>
@@ skipping 809 matching lines @@
                {ui::EF_ALTGR_DOWN, "Mod5"},
                {ui::EF_MOD3_DOWN, "Mod3"},
                {ui::EF_CAPS_LOCK_ON, XKB_MOD_NAME_CAPS}};
   xkb_flag_map_.clear();
   xkb_flag_map_.resize(arraysize(flags));
   for (size_t i = 0; i < arraysize(flags); ++i) {
     xkb_mod_index_t index = xkb_keymap_mod_get_index(keymap, flags[i].xkb_name);
     if (index == XKB_MOD_INVALID) {
       DVLOG(3) << "XKB keyboard layout does not contain " << flags[i].xkb_name;
     } else {
+      if (flags[i].ui_flag == ui::EF_SHIFT_DOWN)
+        xkb_mod_indexes_.shift = index;
+      else if (flags[i].ui_flag == ui::EF_CONTROL_DOWN)
+        xkb_mod_indexes_.control = index;
+      else if (flags[i].ui_flag == ui::EF_ALT_DOWN)
+        xkb_mod_indexes_.alt = index;
+
       xkb_mod_mask_t flag = static_cast<xkb_mod_mask_t>(1) << index;
       XkbFlagMapEntry e = {flags[i].ui_flag, flag};
       xkb_flag_map_.push_back(e);
     }
   }
 
   // Update num lock mask.
   num_lock_mod_mask_ = 0;
   xkb_mod_index_t num_mod_index =
       xkb_keymap_mod_get_index(keymap, XKB_MOD_NAME_NUM);
@@ skipping 128 matching lines @@
     if (close_index == std::string::npos)
       close_index = layout_name.size();
     *layout_variant = layout_name.substr(parentheses_index + 1,
                                          close_index - parentheses_index - 1);
   } else if (dash_index != std::string::npos) {
     *layout_id = layout_name.substr(0, dash_index);
     *layout_variant = layout_name.substr(dash_index + 1);
   }
 }
 
+int XkbKeyboardLayoutEngine::UpdateModifiers(uint32_t depressed_mods,
+                                             uint32_t latched_mods,
+                                             uint32_t locked_mods,
+                                             uint32_t group) {
+  xkb_state_update_mask(xkb_state_.get(), depressed_mods, latched_mods,
+                        locked_mods, 0, 0, group);
+
+  int modifiers = 0;
+  auto component = static_cast<xkb_state_component>(XKB_STATE_MODS_DEPRESSED |
+                                                    XKB_STATE_MODS_LATCHED);
+  if (xkb_state_mod_index_is_active(xkb_state_.get(), xkb_mod_indexes_.control,
+                                    component))
+    modifiers |= EF_CONTROL_DOWN;
+  if (xkb_state_mod_index_is_active(xkb_state_.get(), xkb_mod_indexes_.alt,
+                                    component))
+    modifiers |= EF_ALT_DOWN;
+  if (xkb_state_mod_index_is_active(xkb_state_.get(), xkb_mod_indexes_.shift,
+                                    component))
+    modifiers |= EF_SHIFT_DOWN;
+
+  return modifiers;
+}
+
 }  // namespace ui