[ozone/wayland] Implement basic keyboard handling support

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

Index: ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
index b72f6f208e3fd8deb9939b8cae47183269bc1802..aacfc8a483a6a5b58dffe71a66e81a261ac5b230 100644
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
+++ b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
@@ -827,6 +827,13 @@ void XkbKeyboardLayoutEngine::SetKeymap(xkb_keymap* keymap) {
     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);
@@ -975,4 +982,27 @@ void XkbKeyboardLayoutEngine::ParseLayoutName(const std::string& layout_name,
   }
 }
 
+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